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| Information about the Demographic Projections |
Availability
| Valid From: .. | 06/30/2006 |
| To: .. | 06/30/2111 12:00:00 AM |
| Frequency: .. | Irregularly |
Design
Purpose: Demographic projections provide an indication of future trends in the size and composition of the population, labour force, families and households. The projections are used for community, business and government planning and policy-making in areas such as health, education, superannuation and transport. The projections are typically updated every two to three years.
General Information ..
Contents
National Projections
Subnational Projections
Alternative Series
Ad hoc and Customised Projections
Different Population Measures
Projection Assumptions
Method
Nature of Projections
National Population Projections
National Ethnic Population Projections
National Family and Household Projections
National Labour Force Projections
Subnational Population Projections
Subnational Ethnic Population Projections
Subnational Family and Household Projections
National Projections
Projections are produced at the national level (New Zealand) for the population (total, Māori ethnicity, Pacific ethnicities, Asian ethnicities, European ethnicities), families, households and labour force. The latest national population projections have as a base the estimated resident population of New Zealand at 30 June 2009 and cover the period to 2061 at one-year intervals.
The latest national ethnic population projections are 2006-base and cover the period to 2026 at one-year intervals. People who identify with more than one ethnicity are included in each ethnic population that they identify with.
The latest national family and household projections are 2006-base and cover the period to 2031 at one-year intervals.
The latest national labour force projections are 2006-base and cover the period to 2061 at one-year intervals.
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Subnational Projections
Projections are produced at the subnational level (regional council areas, city and district council areas) for the population (total, Māori ethnicity, Pacific ethnicity, Asian ethnicity, European ethnicity), families and households. The projections of the total population are also available for area units ('suburbs'), urban areas and zones. The ethnic population projections are produced for most regions and some territorial authority areas depending on the size of the respective ethnic base population.
Statistics New Zealand adopts a 'top-down' approach to demographic projections. This means that projections are first completed at the national level. These subsequently serve as a constraint for projections for territorial authority areas. In turn, territorial authority projections serve as a constraint for projections for smaller areas (eg area units). The advantages of this top-down approach include quicker release of projections for larger areas and avoidance of implausible projections for larger areas.
The latest subnational population projections and subnational family and household projections have as a base the estimated resident population of each area at 30 June 2006 and cover the period to 2031 at five-year intervals.
The latest subnational ethnic population projections are 2006-base and cover the period to 2021 at five-year intervals.
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Alternative Series
A number of alternative series are produced for each set of projections using different combinations of appropriate assumptions about future fertility, mortality, migration, inter-ethnic mobility, living arrangement type and labour force participation patterns of the population.
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Ad hoc and Customised Projections
Special projections can be produced for clients using their own assumptions. For more information and quotes, email demography@stats.govt.nz or telephone 0508 525 525 toll free.
For customised projections, Statistics New Zealand takes responsibility for the method employed but the assumptions used are the final responsibility of the client and the projections are not official Statistics New Zealand population statistics.
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Different Population Measures
There are two main population concepts of interest:
- all the people present in a given area at a given time (the 'de facto population concept')
- all the people who usually live in a given area at a given time (the 'resident population concept').
Both of these populations can be counted or estimated.
Population counts
The New Zealand Census of Population and Dwellings counts people where they are on census night (census night population count). As this may not be where they usually live, respondents are also asked to provide the address of their place of usual residence (census usually resident population count).
A person's usual address is generally self-identified. Visitors intending to be in New Zealand for less than 12 months are generally considered to usually live overseas.
Population estimates
To provide population data between census dates, Statistics New Zealand estimates the population, using the most recent census data as a base. The estimated resident population is updated regularly for population changes due to births, deaths and net migration (arrivals less departures) of residents. The estimate gives the best measure of the population that usually lives in an area, for a limited range of variables (age, sex, ethnicity) and limited geographic areas. Population estimates apply either to the number of people at a particular time ('as at') or the average over a period of time ('mean'), usually a year.
Population projections
Estimates of the total size or composition of the population at a future date are based on certain assumptions about future fertility, mortality and migration. The projected resident population has as a base the estimated resident population at a given date.
Population measures
Historically, population data comprised counts of all people present in an area at a given time. However, increased geographic mobility means people are more likely to move between New Zealand and overseas, and between areas of New Zealand, for work, study and holidays. There is therefore a need for data on the people who usually live in an area at a given time, as this is more relevant for many planning purposes (eg housing, schools).
The question often arises as to what is the best measure of the population of an area. This partly depends on what use will be made of that population measure, and what information is available to calculate the population measure. In some instances it may be appropriate to exclude/include visitors who are temporarily present in an area and residents who are temporarily absent from an area.
There are three population measures commonly produced by Statistics New Zealand:
- Census night population count: A count of all people present in a given area on a given census night.
The census night population count of New Zealand is a count of all people present in New Zealand on a given census night. It includes visitors from overseas who are counted on census night, but excludes New Zealand residents who are overseas (temporarily or permanently).
The census night population count of an area in New Zealand is a count of all people present in that area on a given census night. This count includes visitors from elsewhere in New Zealand and visitors from overseas who are counted on census night, but excludes residents of that area who are temporarily elsewhere in New Zealand or overseas on census night.
- Census usually resident population count: A count of all people present in New Zealand who usually live in a given area on a given census night.
The census usually resident population count of New Zealand is a count of all people who usually live, and are present, in New Zealand on a given census night. It excludes visitors from overseas and excludes residents who are overseas on census night (temporarily or permanently).
The census usually resident population count of an area in New Zealand is a count of all people who usually live in that area and are present in New Zealand on a given census night. This count excludes visitors from overseas, visitors from elsewhere in New Zealand, and residents temporarily overseas on census night.
This count is obtained by including people in the meshblock (smallest geographic area for statistical purposes) of their usual address. Those who are temporarily elsewhere in New Zealand on a given census night are included in the meshblock they usually live in.
- Estimated resident population: An estimate of all people who usually live in a given area at a given date.
The estimated resident population of New Zealand is an estimate of all people who usually live in New Zealand at a given date. It includes all residents present in New Zealand and counted by the census (census usually resident population count), residents who are temporarily overseas (who are not included in the census), and an adjustment for residents missed or counted more than once by the census (net census undercount). Visitors from overseas are excluded.
The estimated resident population of an area in New Zealand is an estimate of all people who usually live in that area at a given date. It includes all residents present in New Zealand and counted by the census (census usually resident population count), residents who are temporarily overseas (who are not included in the census), and an adjustment for residents missed or counted more than once by the census (net census undercount). Visitors from elsewhere in New Zealand and from overseas are excluded.
The estimated resident population at a given date after census also includes an update for births, deaths and net migration of residents during the period between census date and the given date. National population estimates are produced quarterly (reference dates at 31 March, 30 June, 30 September and 31 December) and subnational population estimates are produced annually (reference date at 30 June).
The following table summarises the inclusions and exclusions of each population measure for an area in New Zealand on census night:
| Group | Census night population count | Census usually resident population count | Estimated resident population(1) |
| Residents who are present | Yes | Yes | Yes |
| Residents who are temporarily elsewhere in New Zealand | No | Yes | Yes |
| Residents who are temporarily overseas | No | No | Yes |
| Visitors from elsewhere in New Zealand | Yes | No | No |
| Visitors from overseas | Yes | No | No |
(1) Usually includes an adjustment for net census undercount of residents. For a given date after census, the estimated resident population is also updated for births, deaths and net migration (arrivals less departures) of residents during the period between census night and the given date.
The following table illustrates the differences between the three population measures in 2001:
In a major change from historical practice, all population estimates, population projections and derived demographic indices produced by Statistics New Zealand from 1991 adopt the resident population concept. Previously, these figures were based on the de facto population concept. Statistics New Zealand has adopted the resident population concept to ensure that population estimates reflect more accurately the population that usually lives in each area. This concept is preferred for most central and local government administration and planning purposes. Further information on the resident population concept is provided in the Demographic Trends 1996 article 'The 1996 Post Enumeration Survey (PES) and Post-censal Population Estimates'.
Important
Population estimates and projections are not directly comparable with census counts. Census counts give a snapshot of the population at that time but make no allowance for New Zealand residents temporarily overseas or for net census undercount.
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Projection Assumptions
Projection assumptions are formulated after analysis of short-term and long-term demographic trends, patterns and trends observed in other countries, government policy, information provided by local planners and other relevant information. Where the same type of projections are produced at both national and subnational levels, assumptions are set first for the national series and used as a guide for the subnational projection assumptions. The medium variant subnational series is designed to align with the medium variant national series. However, the range (difference between the low and high variants) for subnational series is generally greater than for New Zealand as a whole. Moreover, the low and high projection series for subnational areas are independent of any series of national population projections as they represent plausible alternative scenarios for each area rather than for any aggregate geographic level.
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Method
The cohort component method has been used to derive all demographic projections. By this method, the base population is projected forward by calculating the effect of deaths and migration within each age-sex group according to specified mortality and migration assumptions. New birth cohorts are generated by applying specified fertility assumptions to the female population of childbearing age. For projections of ethnic populations, families, households and labour force, additional components of change are also incorporated as described below for each projection type.
Assumptions for national projections are derived for each single-year of age to produce projections at one-year intervals. The following describes how assumptions are applied for national projections. For subnational projections, a similar approach is applied to five-year age groups to produce projections at five-year intervals.
Fertility
Projected (live) births are derived by applying age-specific fertility rates to the mean female population of childbearing age. The mean female population for each age is derived by averaging the population at the start and end of each year. The sum of the number of births derived for each age of mother gives the projected number of births for each year.
The female age-specific fertility rates for each year of the projection period represent the number of births to females of each age in each year. The set of age-specific fertility rates for each year is typically summarised by the total fertility rate.
For all population projections, a sex ratio at birth of 105.5 males per 100 females is assumed, based on the historical annual average of the total population.
The fertility assumptions should not be used as a precise measure of fertility or of fertility differentials between groups. It is important to note that the objective of population projections is not to specifically measure or project the fertility of the population. For projection purposes it is more important to have a realistic yet tractable model for projecting fertility trends (and birth numbers) into the future.
Mortality
Mortality assumptions are formulated in terms of survival rates. This is because in the projection model the base population is survived forward each year. The projected number of deaths is calculated indirectly. Survival rates are applied to births, ages 0–99 years, and age group 100 years and over. There are different survival rates for each age of life and for males and females.
The male and female age-specific survival rates for each year of the projection period represent the proportion of people at each age-sex who will survive for another year. In general, survival rates are highest at ages 5–11 years and then decrease with increasing age. The set of age-sex-specific survival rates for each year is typically summarised by male and female life expectancies at birth.
Annual survival rates are applied separately to the population at the start of each year, births and migrants.
The mortality assumptions should not be used as a precise measure of mortality or of mortality differentials between groups. It is important to note that the objective of population projections is not to specifically measure or project the life expectancy of the population. For projection purposes it is more important to have a realistic yet tractable model for projecting mortality trends (and death numbers) into the future.
Migration
Migration assumptions are formulated in terms of a net migration level and an age-sex net migration pattern for each year of the projection period. Where practical, both the level and age-sex pattern are derived from a detailed analysis of net migration, including:
- external migration data (from passenger cards):
- arrivals and departures by country of citizenship
- New Zealand citizen arrivals and departures by country of source/destination
- Immigration New Zealand data:
- residence applications and approvals
- student and work permits
- Ministry of Education figures on students from overseas in formal education.
For subnational migration assumptions, the net migration level and age-sex net migration pattern for each five-year interval of the projection period are not a mere extrapolation of past trends, but take into account:
- age-specific net migration rates, so that net migration relative to the population of each birth cohort is plausible
- non-private dwellings – such as universities, prisons, military bases, hospitals, rest homes, retirement villages – which can significantly affect migration levels and patterns
- residential building consents
- information available from and about local authorities relating to current and future developments which may affect population change
- historical levels and patterns of migration from census and estimates.
Statistics New Zealand has been investigating alternative methods of formulating migration assumptions for subnational population projections. For a discussion of alternative methods, see Bell M and Wilson T ("Comparative empirical evaluations of internal migration models in subnational population projections", Journal of Population Research, Vol. 21 No. 2, pg127–160, 2004). As with any alternative and new method, the impact on the usefulness of the projections needs to be evaluated relative to the costs, complexity and transparency for users and producers of the projections. While each alternative method offers advantages, some of the key advantages of the current net migration model are:
- method can be applied to all necessary geographic levels (New Zealand, territorial authority areas, area units)
- low data requirements compared with models which require more complex data (eg migration disaggregated by arrivals and departures and/or by internal migration and external migration, by age-sex) – robust estimates at a disaggregated level are often not available
- relative ease of application which limits the time and costs of production.
Ethnicity is not collected in external migration data, but the migration assumptions are based on an assessment of recent and expected trends of arrivals and departures of New Zealand citizens and non-New Zealand citizens by birthplace, as well as observed intercensal ethnic population change.
Application
For each projection year the assumptions are applied thus:
- survive the population alive at the start of the year
- derive the number of migrants by age and sex
- survive the migrants
- derive the number of births (by applying fertility rates to mean of female population at start and end of the year)
- survive the births.
For ethnic population projections, additional assumptions are applied thus:
- survive the population alive at the start of the year
- derive the number of migrants by age and sex
- survive the migrants
- adjust the population to account for inter-ethnic mobility (by applying rates to the population at the start of the year)
- derive the number of births (by applying fertility rates to mean of female population at start and end of the year, and applying paternity rates to mean of male population at start and end of the year)
- adjust the births to account for births to parent(s) of that ethnicity that are not registered as children of that ethnicity (by applying net rate to projected births)
- survive the births.
Population (at start of the year)
For the population already present in the country at the start of the year, the number alive at the end of the year is calculated as:
Survived Population = Population x Survival Rate
There are different survival rates for each age of life, from age 0 to age 100+ years, and for males and females.
Births
Births occur throughout a year and not all children born during a year will be alive at the end of the year. For this reason a survival rate for births is needed:
Survived Births = Births x (1 + Survival Rate) / 2
This formula is derived by taking the average of:
- assuming all births occurred on 1 July (the first day of the year) of each year, and
- assuming all births occurred on 30 June (the last day of the year) of each year.
If all births occurred on 1 July then the births have to be survived over a whole year. If all births occurred on 30 June then there would be no deaths and hence there is no need to apply a survival rate. The average of these two is taken because births occur throughout the year.
Migrants
A similar mathematical formula is used to survive the migrants for each age:
Survived Migrants = Migrants x (1 + Survival Rate) / 2
The assumption is made that either all migration occurs on the first day of the year or all migration occurs on the last day of the year. The average is then taken because migration occurs throughout the year.
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Nature of Projections
Demographic projections are designed to meet both short-term and long-term planning needs, but are not designed to be exact forecasts or to project specific annual variation. Demographic projections are based on assumptions about future fertility, mortality, migration, inter-ethnic mobility, living arrangement type and labour force participation patterns of the population. Although the assumptions are carefully formulated to represent future trends, they are subject to uncertainty. Therefore, the projections should be used as guidelines and an indication of the overall trend, rather than as exact forecasts.
Demographic projections should not be confused with economic forecasts. Changes in the number of people, families, and households do not necessarily relate to the social and economic well-being of an area. The number of people, families, and households may change independently of local economic factors.
The projections do not take into account non-demographic factors (eg war, catastrophes, major government and business decisions, changes to the ethnic classification) which may invalidate the projections. Demographic trends are monitored regularly and, when it is necessary, the projections are revised to reflect new trends and to maintain their relevance and usefulness.
Subnational, ethnic, and family and household projections have shorter projection periods than other projections because of their greater uncertainty. Subnational projections are most affected by the unpredictability of migration trends, especially in the short term, which can have a significant effect on projection results.
Ethnic projections
Projections of ethnic populations are more uncertain than projections of the total population for several reasons:
- Ethnic identification can change over time. This may reflect a person's cultural affiliations changing over time. Or, it may occur when different people respond to the ethnicity question. For example, the ethnicity of babies and young children is usually identified by their parents. However, in a later census when these children are old enough to complete their own forms, they will decide for themselves which ethnicity they identify with. This may differ from the ethnicity identified by their parents. Inter-ethnic mobility can also occur when different ethnicities are reported in different collections (eg birth registration form, death registration form, census form) for a person.
- There are greater difficulties in establishing past trends in fertility, mortality and migration. Different ethnicities can be reported in different collections (eg birth registration form, death registration form, census form), which makes the derivation of ethnic-specific fertility and mortality rates problematic. Furthermore, the measurement of ethnicity has changed over time in many collections, while it is not captured at all in some collections (eg international travel and migration data).
- Ethnic populations are not mutually exclusive because people can and do identify with more than one ethnicity. People are not asked to prioritise their ethnic responses. Hence, Statistics New Zealand includes people in each of their reported ethnic groups.
- There is the added complication of births to parents of different ethnicities. The child may be considered by the parents to belong to one or more of their ethnicities, or indeed to another ethnicity.
- There is greater future uncertainty about the components of population change. For example, it is uncertain whether the fertility and mortality of different ethnicities will converge, and if so, at what pace. Assumptions about future migration, notably for people of Asian and Pacific ethnicities, are particularly susceptible to changes in migration patterns.
Statistics NZ incorporates these issues into its methodology for ethnic population projections and develops alternative projection scenarios to illustrate uncertainty. However, it is because of these issues that ethnic population projections are limited to broad ethnic groups and the given projection period. For smaller ethnic populations it is difficult to derive robust measures of fertility and mortality and the other components of ethnic population change to enable projections to be readily produced. The subnational ethnic population projections are further limited to selected geographic areas because of the small size of many subnational ethnic populations.
Family and household projections
Household numbers should not be confused with building activity or dwelling numbers. 'Households' refer to private dwellings that are usually occupied by a person or group of people. Households therefore exclude non-private dwellings, unoccupied dwellings, and dwellings which are not the usual residence of people (eg holiday homes, second homes).
Projections of families and households are also affected by the uncertainty about how different social patterns will interrelate and vary by age-sex and/or birth cohort. Relevant social patterns include changes in:
- age of cohabitation and/or marriage
- fertility rates, timing of childbearing, and average family size
- morbidity and mortality rates
- rates of partnership formation, including repartnering, and dissolution
- propensity of young adults to stay in the parental home
- propensity and ability of people to live alone
- propensity of older people to live in aged-care facilities
- presence of other relatives (eg extended family) and non-related individuals (eg boarders) in a household
- study, work, and shared-care arrangements where people are associated with more than one household
- geographic location and mobility of the population
- external migration patterns, including students from overseas
- affordability of tertiary education, housing, and health care
- ethnic mix of the New Zealand population.
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National Population Projections
Projections (2009-base to 2061) of the population usually living in New Zealand were released via Hot Off the Press (ISSN 1178-0584) on 27 October 2009. These supersede the projections (2006-base to 2061) released via Hot Off the Press (ISSN 1178-0584) in October 2007.
2009-base to 2061
Base population
These projections have as a base the estimated resident population (provisional) of New Zealand at 30 June 2009. This population (4.316 million) was derived from the estimated resident population of New Zealand (4.185 million) at 30 June 2006, updated for births, deaths and net migration between 30 June 2006 and 30 June 2009 (+131,000). The estimated resident population of New Zealand at 30 June 2009 was derived from the census usually resident population count (4.028 million) at 7 March 2006 with adjustments for:
- net census undercount (+80,000)
- residents temporarily overseas on census night (+64,000)
- births, deaths and net migration between census night (7 March 2006) and 30 June 2006 (+9,000)
- reconciliation with demographic estimates at ages 0–4 years (+3,000).
For more information about the base population, refer to Population Estimates.
Alternative series
Nine alternative series have been produced using different combinations of fertility, mortality and migration assumptions. At the time of release, projection series 5 is considered the most suitable for assessing future population changes. The other projection series allow users to assess the impact on population size and structure resulting from changes in the assumptions for each of the components of population change. Series 4, 5 and 6 can be used for assessing the effect of the different migration assumptions; series 3, 5 and 7 allow for a comparative mortality analysis; and series 2, 5 and 8 allow for a comparative fertility analysis.
Series 1 and 9 give the lowest and highest projected population, respectively, based on the adopted assumptions. Series 1 uses low fertility, high mortality and low net migration. Series 9 uses high fertility, low mortality and high net migration.
Five additional series have also been produced to illustrate how the population will change if certain demographic events were to occur:
- The total fertility rate increases from 2.14 births per woman in 2009 to 2.21 in 2011, 2.37 in 2016, 2.46 in 2021, 2.50 in 2026, and then remains constant.
- Life expectancy at birth increases at a similar annual rate as between the 1975–77 and 2005–07 complete period life tables (ie by 0.30 and 0.22 years of life for males and females, respectively) to reach 95.0 years of life for both males and females in 2061.
- No external migration at any age throughout the projection period (ie a 'closed' population).
- Annual net migration fluctuates between -10,000 and 30,000 over a 10-year cycle, with an annual average of 10,000.
- Annual net migration of 25,000 throughout the projection period.
More detailed projection results, including projections for individual years or projections by age and sex, are available from the Statistics New Zealand website or on request. Special projections can also be produced for clients using their own assumptions. For more information and quotes, email demography@stats.govt.nz or phone toll-free 0508 525 525.
Summary table of assumptions
The projection assumptions for the New Zealand population are summarised in the following table.
 (36 KB)
Fertility
There are three alternative fertility variants – designated low, medium and high – which assume that fertility rates will vary until the year 2026 when the total fertility rate will reach 1.70, 1.90 and 2.10 births per woman, respectively. After 2026, fertility rates are assumed to stay constant. The total fertility rate in the year ended June 2009 was 2.14 births per woman (based on births by date of registration).
Assumed total fertility rates
 | Average total fertility rate (births per woman)
in period ended 30 June |
Fertility variant | 20091 | 2012-16 | 2017-21 | 2022-26 |
| Low | 2.14 | 1.90 | 1.77 | 1.71 |
| Medium | 2.14 | 2.02 | 1.94 | 1.91 |
| High | 2.14 | 2.14 | 2.11 | 2.10 |
(1) Based on births by date of registration, rather than by date of occurrence.
The medium fertility variant assumes fertility rates of women aged under 32 years will decline between 2009 and 2026, but increase for women aged 32 years and over. By comparison, the low fertility variant assumes fertility rates will decrease between 2009 and 2026 at most ages. The high fertility variant assumes that fertility rates of women aged under 32 years will drop between 2009 and 2026, but increase for women aged 32 years and over.
Assumed age-specific fertility rates1
| Births per 1,000 women | Total fertility rate |
Year ended
30 June | 10-14 | 15-19 | 20-24 | 25-29 | 30-34 | 35-39 | 40-44 | 45-49 |
| 20092 | 0.23 | 31 | 78 | 109 | 123 | 70 | 14 | 0.65 | 2.14 |
| 2026 low | 0.10 | 16 | 47 | 79 | 113 | 72 | 12 | 0.70 | 1.70 |
| 2026 medium | 0.15 | 20 | 55 | 87 | 122 | 80 | 15 | 0.85 | 1.90 |
| 2026 high | 0.20 | 24 | 63 | 95 | 131 | 88 | 18 | 1.00 | 2.10 |
(1) Approximate only as fertility rates are actually applied by single-year of age.
(2) Based on births by date of registration, rather than by date of occurrence.
A sex ratio at birth of 105.5 males per 100 females is assumed, based on the historical annual average of the New Zealand population.
Mortality
There are three alternative mortality variants – designated low, medium and high – which assume that mortality rates will continue to drop so that the period life expectancy at birth for males will increase to 88.6, 85.6 and 82.6 years, respectively, by 2061. The corresponding life expectancies for females in 2061 will be 91.2, 88.7 and 86.2 years. The life expectancy at birth in 2005–07, from complete period life tables, was 78.0 years for males and 82.2 years for females.
Mortality rates are assumed to decrease at different rates at different ages. Between 2006 and 2061, male mortality rates are assumed to decrease by an average of 2.1, 1.6 and 1.0 percent per year for the low, medium and high mortality variants, respectively. By comparison, female mortality rates are assumed to decrease by an average of 2.4, 1.8 and 1.3 percent per year for the low, medium and high mortality variants, respectively.
Statistics NZ has investigated some alternative methods for projecting mortality based on the observed age-and-sex-specific trends in period and cohort life table data. These 2009-base projections adopt a new method in which the mortality assumptions are essentially driven by the observed trends in death rates by birth cohort, age and sex.
Previous mortality assumptions were based on a review of those assumptions against observed trends, analysis of the latest cohort and period measures of death rates and life expectancy by age-sex, and international comparisons of mortality and longevity. The international comparisons were important for several reasons for this. First, there was an expectation that larger countries had greater research capabilities with which to investigate and formulate mortality assumptions. Second, the larger numbers of deaths and people in other countries made death rates more reliable, especially at the oldest ages. Third, a comparison of mortality levels and patterns with other countries was a useful check on plausibility. New Zealand life expectancy assumptions were broadly consistent with those of national statistical agencies in Australia, Canada, Japan, United Kingdom, and the United States.
Previous Statistics NZ projections also assumed that mortality rates would decrease at the same rate at all ages, albeit with different male and female rates of decrease. Changes in death rates by age-sex have been inconsistent from period to period, possibly because of both cohort and period effects. This made it difficult to formulate different future rates of mortality decrease by age. Moreover, the relative lower rates of decrease at some ages may point to greater potential for future decreases at these ages. Hence, given uncertainty as to how future changes will vary by age, rates of change were assumed the same across all ages.
The new mortality assumptions for the 2009-base projections are based on observed age-specific death rates from complete cohort life tables for 1876-2007 birth cohorts. The cohort life tables are based on mortality rates experienced by a birth cohort (people born in the same year) at each age-sex over their lifetime. In contrast, period life tables are based on mortality rates in a particular period. Intuitively, cohort life tables appear preferable to period life tables as a basis for formulating assumptions about future mortality. The cohort life tables were first published in 2006, and are updated and extended each year. For more information, refer to cohort life tables on the Statistics NZ website (www.stats.govt.nz) and the technical report A History of Survival in New Zealand: Cohort life tables 1876–2004.
In the new method, exponential curves are fitted to historical cohort mortality data for each age-sex. Exponential curves generally fit the historical data well, and cannot generate negative values when extrapolated. The suitability of exponential curves is largely based on the asymptotic nature of mortality (and survival) as death rates approach zero (and survivorship rates approach unity) over time.
Complete cohort life tables are derived for selected birth cohorts (eg 1956, 2006, 2061) and intermediate cohorts are interpolated. Cohort survivorship rates are then transformed to period survivorship rates, with some adjustment to give plausible death numbers by age-sex in the initial years of the projection period. The low and high mortality variants are formulated relative to the medium variant to give alternative but plausible mortality scenarios.
International comparisons of mortality and longevity continue to serve as a useful check on plausibility. Despite differences in methods, the New Zealand life expectancy assumptions are broadly consistent with the latest available projection assumptions from national statistical agencies in Australia, Canada, Japan, United Kingdom, and the United States.
As with all projection assumptions, implied changes over time should not be interpreted as meaning stability in future mortality patterns. Merely, that the projections are a simplification of complex and variable phenomenon with the assumptions designed to convey future average long-run patterns.
Migration
There are three alternative migration variants – designated low, medium and high – which assume long-run annual net migration of 5,000, 10,000 and 15,000, respectively. The medium migration variant assumes net migration of 25,000 in 2010, 19,000 in 2011, and 14,000 in 2012. The low and high migration variants are 5,000 lower and higher, respectively, than the medium variant for each year. These levels are based on an analysis of immigration permits, residence applications and approvals, overseas student numbers, and arrivals and departures analysed by characteristics such as citizenship, country of last/next permanent residence and age.
Consistent with historical and recent trends, the age-sex patterns of net migration assume the main net outflow at ages 22–25 years, mainly due to young New Zealanders embarking on overseas travel and the departure of students from overseas after studying in New Zealand. Net inflows are assumed for most other ages with the highest net inflows at 15–20 and 27–37 years.
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2006-base to 2061
Base population
These projections have as a base the estimated resident population of New Zealand at 30 June 2006. This population (4.185 million) was derived from the census usually resident population count (4.028 million) at 7 March 2006 with adjustments for:
- net census undercount (+80,000)
- residents temporarily overseas on census night (+64,000)
- births, deaths and net migration between census night (7 March 2006) and 30 June 2006 (+9,000)
- reconciliation with demographic estimates at ages 0–4 years (+3,000).
For more information about the base population, refer to Population Estimates.
Alternative series
Nine alternative series have been produced using different combinations of fertility, mortality and migration assumptions. At the time of release, projection series 5 is considered the most suitable for assessing future population changes. The other projection series allow users to assess the impact on population size and structure resulting from changes in the assumptions for each of the components of population change. Series 4, 5 and 6 can be used for assessing the effect of the different migration assumptions; series 3, 5 and 7 allow for a comparative mortality analysis; and series 2, 5 and 8 allow for a comparative fertility analysis.
Series 1 and 9 give the lowest and highest projected population, respectively, based on the adopted assumptions. Series 1 uses low fertility, high mortality and low net migration. Series 9 uses high fertility, low mortality and high net migration.
Five additional series have also been produced to illustrate how the population will change if certain demographic events were to occur:
- The total fertility rate increases from 1.99 births per woman in 2006 to 2.27 in 2011, 2.39 in 2016, 2.47 in 2021, 2.50 in 2026, and then remains constant.
- Life expectancy at birth increases at a similar annual rate as between the 1975–77 and 2005–07 complete period life tables (ie by 0.31 and 0.23 years of life for males and females, respectively) to reach 95.0 years of life for both males and females in 2061.
- No external migration at any age throughout the projection period (ie a 'closed' population).
- Annual net migration fluctuates between -10,000 and 30,000 over a 10-year cycle, with an average of 10,000.
- Annual net migration of 25,000 throughout the projection period.
More detailed projection results, including projections for individual years or projections by age and sex, are available from the Statistics New Zealand website or on request. Special projections can also be produced for clients using their own assumptions. For more information and quotes, email demography@stats.govt.nz or phone toll-free 0508 525 525.
Summary table of assumptions
The projection assumptions for the New Zealand population are summarised in the following table.
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Fertility
There are three alternative fertility variants – designated low, medium and high – which assume that fertility rates will vary until the year 2026 when the total fertility rate will reach 1.70, 1.90 and 2.10 births per woman, respectively. After 2026, fertility rates are assumed to stay constant. The base total fertility rate in 2006 was 1.99 births per woman (based on estimated births by date of occurrence).
Assumed total fertility rates
| Average total fertility rate (births per woman)
in period ended 30 June |
Fertility variant | 2006 (base)1 | 2007-11 | 2012-16 | 2017-21 | 2022-26 |
| Low | 1.99 | 2.01 | 1.86 | 1.76 | 1.71 |
| Medium | 1.99 | 2.09 | 2.00 | 1.94 | 1.91 |
| High | 1.99 | 2.17 | 2.15 | 2.12 | 2.10 |
(1) Based on estimated births by date of occurrence, rather than by date of registration.
The medium fertility variant assumes fertility rates of women aged under 32 years will decline between 2006 and 2026, while rates for women aged 32 years and over will increase. By comparison, the low fertility variant assumes fertility rates will decrease between 2006 and 2026 for most ages. The high fertility variant assumes that fertility rates will drop between 2006 and 2026 for women aged under 31 years and increase for women aged 31 years and over.
Assumed age-specific fertility rates1
| Births per 1,000 women | Total fertility rate |
Year ended
30 June | 10-14 | 15-19 | 20-24 | 25-29 | 30-34 | 35-39 | 40-44 | 45-49 |
| 2006 (base)2 | 0.19 | 27 | 69 | 105 | 119 | 64 | 12 | 0.63 | 1.99 |
| 2026 low | 0.10 | 16 | 45 | 82 | 117 | 68 | 12 | 0.69 | 1.70 |
| 2026 medium | 0.15 | 20 | 53 | 90 | 125 | 76 | 15 | 0.86 | 1.90 |
| 2026 high | 0.20 | 24 | 61 | 98 | 134 | 84 | 18 | 1.02 | 2.10 |
(1) Approximate only as fertility rates are actually applied by single-year of age.
(2) Based on estimated births by date of occurrence, rather than by date of registration.
A sex ratio at birth of 105.5 males per 100 females is assumed, based on the historical annual average of the New Zealand population.
Mortality
There are three alternative mortality variants – designated low, medium and high – which assume that mortality rates will continue to drop so that the life expectancy at birth for males will increase to 87.0, 84.5 and 82.0 years, respectively, by 2061. The corresponding life expectancies for females in 2061 will be 90.0, 88.0 and 86.0 years. The base life expectancy at birth in 2005–07 was 78.2 years for males and 82.2 years for females.
Mortality rates are assumed to decrease at the same rate at all ages. Between 2006 and 2061, male mortality rates are assumed to decrease by about 55, 44 and 29 percent for the low, medium and high mortality variants, respectively. By comparison, female mortality rates are assumed to decrease by about 53, 44 and 31 percent for the low, medium and high mortality variants, respectively.
Migration
There are three alternative migration variants – designated low, medium and high – which assume long-run annual net migration levels of 5,000, 10,000 and 15,000, respectively. Short-run migration levels converging to the long-run levels are assumed for 2007–09. These short-run levels are based on an analysis of immigration permits, residence applications and approvals, overseas student numbers, and arrivals and departures analysed by characteristics such as citizenship, country of last/next permanent residence and age.
Consistent with historical and recent trends, the age-sex patterns of net migration assume the main net outflow at ages 21–25 years, mainly due to young New Zealanders embarking on overseas travel and the departure of students from overseas after studying in New Zealand. Net inflows are assumed for most other ages with the highest net inflows at 15–19 and 27–38 years.
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National Ethnic Population Projections
Projections (2006-base to 2026 update) of the populations of 'European or Other (including New Zealander)', Māori, Asian and Pacific ethnicities usually living in New Zealand were released via Hot Off the Press (ISSN 1178-0592) on 22 April 2010. These supersede the projections (2006-base to 2026) released via Hot Off the Press (ISSN 1178-0592) in April 2008.
Ethnic concept
The ethnic concept used in these projections is the ethnic group or groups that people identify with or feel they belong to. Ethnicity is self-perceived and people can belong to more than one ethnic group. For example, people may identify with the Māori ethnicity even though they are not descended from a Māori ancestor. Conversely, people may choose to not identify with the Māori ethnicity even though they are descended from a Māori ancestor. Ethnicity is not the same as birthplace.
People who identify with more than one ethnicity are included in each ethnic population. Therefore, the ethnic population projections are not mutually exclusive.
For more information about ethnicity, refer to the Review of the Measurement of Ethnicity which includes information about the Statistical Standard for Ethnicity 2005.
Alternative series
For each ethnic group, eleven alternative series have been produced using different combinations of fertility, mortality, migration and inter-ethnic mobility assumptions. At the time of release, projection series 6 is considered the most suitable for assessing future population changes. The other projection series allow users to assess the impact on population size and structure resulting from changes in the assumptions for each of the components of population change. Series 2, 6 and 10 can be used for assessing the effect of the different fertility assumptions; series 3, 6 and 9 allow for a comparative mortality analysis; series 4, 6 and 8 allow for alternative migration levels; and series 5, 6 and 7 allow for different inter-ethnic mobility rates.
Series 1 and 11 give the lowest and highest projected population, respectively, based on the adopted assumptions. Series 1 uses low fertility, high mortality, low migration and high inter-ethnic mobility. Series 11 uses high fertility, low mortality, high migration and low inter-ethnic mobility.
Method
A special cohort component method has been used to derive the ethnic population projections. By this method, the base population is projected forward by calculating the effect of deaths, migration and inter-ethnic mobility within each age-sex group according to specified mortality, migration and inter-ethnic mobility assumptions. New birth cohorts are generated by applying specified fertility assumptions to the female population of childbearing age, and specified paternity assumptions to the male population.
The method differs from the conventional cohort component method in two respects:
- For each ethnic group, births are projected separately for women, and for men where the mother is not of that ethnic group. For example, Māori births have been projected separately for Māori women, and for Māori men where the mother is non-Māori.
- The projections allow for population change due to inter-ethnic mobility (ie people changing their ethnic identification over time).
Fertility and mortality assumptions are derived for the purpose of projecting each population and should not be used as a precise measure of fertility or mortality differentials between ethnic groups.
European or Other
Projections have been derived for the 'European or Other (including New Zealander)' ethnic group. Projections are not available for the European ethnic group, or for the Other (including New Zealander) ethnic group. This reflects that sufficient demographic data is available to enable projection assumptions to be derived for the combined ethnic grouping, but not for the separate ethnic groups. This approach is consistent with Guidelines for Using Ethnicity Data: 2006 Census.
2006 Census
The 2006 Census asked people "Which ethnic group do you belong to? Mark the space or spaces which apply to you." The census usually resident population count of 4,027,947 included 2,997,930 people who identified with a 'European or Other' ethnicity, 565,329 who identified with the Māori ethnicity, 354,552 who identified with an Asian ethnicity, 265,974 who identified with a Pacific ethnicity, 34,746 who identified with a Middle Eastern/Latin American/African (MELAA) ethnicity and 167,784 who gave no specific ethnic response.
At the 2006 Census, the number of people identifying with various European or Other ethnicities was: New Zealand European 2,381,076, New Zealander 429,429, English 44,202, Dutch 28,641, British not further defined 27,189, Australian 26,355, European not further defined 21,858, South African not elsewhere classified 21,609, Scottish 15,039, Irish 12,651, German 10,917, American 10,806 and other European or Other groups 55,260. There were 80,088 people who identified with more than one European or Other ethnicity (eg Irish and New Zealander). Of the 2,997,930 European or Other people, 10 percent (302,997) also identified with non-European and non-Other ethnicities. While 84 percent (2,500,047) of people who stated a birthplace were born in New Zealand, 11 percent (314,076) were born in Europe (including the United Kingdom).
Of the 565,329 people identifying with Māori ethnicity at the 2006 Census, 47 percent (266,934) also identified with non-Māori ethnicities. Of those respondents who stated a birthplace, 98 percent (547,302) were born in New Zealand.
At the 2006 Census, the number identifying with various Asian ethnicities was: Chinese (including Taiwanese, etc) 147,570, Indian (including Fijian Indian, etc) 104,583, Korean 30,792, Filipino 16,938, Japanese 11,910, Sri Lankan (including Sinhalese, etc) 8,310, Cambodian 6,918, Thai 6,057, Vietnamese 4,773, Malay 3,540, Indonesian 3,261 and other Asian groups 13,674. There were 3,867 people who identified with more than one Asian ethnicity (eg Chinese and Indian). Of the 354,552 Asian people, 9 percent (32,097) also identified with non-Asian ethnicities. While 20 percent (70,650) of people who stated a birthplace were born in New Zealand, 68 percent (240,537) were born in Asia.
At the 2006 Census, the number of people identifying with various Pacific ethnicities was: Samoan 131,103, Cook Islands Maori (including Rarotongan, etc) 58,008, Tongan 50,481, Niuean 22,476, Fijian 9,864, Tokelauan 6,819 and other Pacific groups 8,907. There were 19,890 people who identified with more than one Pacific ethnicity (eg Samoan and Tongan). Of the 265,974 Pacific people, 30 percent (79,596) also identified with non-Pacific ethnicities. While 60 percent (157,200) of people who stated a birthplace were born in New Zealand, 39 percent (103,176) were born elsewhere in Oceania (including Australia).
For more ethnicity information from the 2006 Census, refer to QuickStats About Culture and Identity and classification counts for ethnic group.
Base population
The 'European or Other (including New Zealander)' population projections have as a base the estimated resident population of European or Other ethnicities of New Zealand at 30 June 2006. This population (3,213,000) was based on the census usually resident population count (2,997,930) at 7 March 2006 with adjustments for:
- non-response to the census ethnicity question (+121,000)
- net census undercount (+50,000)
- residents temporarily overseas on census night (+41,000)
- births, deaths and net migration between census night (7 March 2006) and 30 June 2006 (+2,000)
- reconciliation with demographic estimates at ages 0–4 years (+2,000).
The Māori population projections have as a base the estimated resident population of Māori ethnicity of New Zealand at 30 June 2006. This population (624,000) was based on the census usually resident population count (565,329) at 7 March 2006 with adjustments for:
- non-response to the census ethnicity question (+27,800)
- net census undercount (+18,900)
- residents temporarily overseas on census night (+7,000)
- births, deaths and net migration between census night (7 March 2006) and 30 June 2006 (+4,500)
- reconciliation with demographic estimates at ages 0–4 years (+800).
The Asian population projections have as a base the estimated resident population of Asian ethnicities of New Zealand at 30 June 2006. This population (404,400) was based on the census usually resident population count (354,552) at 7 March 2006 with adjustments for:
- non-response to the census ethnicity question (+17,300)
- net census undercount (+13,600)
- residents temporarily overseas on census night (+14,900)
- births, deaths and net migration between census night (7 March 2006) and 30 June 2006 (+3,700)
- reconciliation with demographic estimates at ages 0–4 years (+300).
The Pacific population projections have as a base the estimated resident population of Pacific ethnicities of New Zealand at 30 June 2006. This population (301,600) was based on the census usually resident population count (265,974) at 7 March 2006 with adjustments for:
- non-response to the census ethnicity question (+18,100)
- net census undercount (+9,100)
- residents temporarily overseas on census night (+4,900)
- births, deaths and net migration between census night (7 March 2006) and 30 June 2006 (+3,000)
- reconciliation with demographic estimates at ages 0–4 years (+500).
For more information about the base population, refer to Population Estimates.
2006-base to 2026 update (released April 2010)
The national ethnic population projections are designed to complement the 2009-base national population projections released in October 2009. However, only mid-range series 6 of the respective ethnic population projections and mid-range series 5 of the New Zealand population projections are designed to be directly comparable. Other series cannot be directly compared because the projection assumptions may be incompatible.
Summary table of assumptions
The projection assumptions for the 'European or Other (including New Zealander)', Māori, Asian and Pacific populations are summarised in the following table.
 (88 KB)
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European or Other (including New Zealander)
Fertility
There are three alternative fertility variants – designated low, medium and high – which assume that fertility rates for European or Other women will vary until the year 2026 when the total fertility rate will reach 1.65, 1.85 and 2.05 births per woman, respectively. The corresponding total paternity rate of European or Other men (with non-European and non-Other women) is assumed to reach 0.115, 0.165 and 0.215 births per man in 2026. The estimated rates in 2005–07 were 1.92 births per European or Other woman and 0.14 births per European or Other man (with non-European and non-Other women).
The medium fertility variant assumes fertility rates of European or Other women aged under 33 years will generally decline between 2007 and 2026, with rates increasing for women aged 33 years and over. The low fertility variant assumes fertility rates of women aged under 34 years will generally decline between 2007 and 2026, with rates increasing for women aged 34 years and over. The high fertility variant assumes fertility rates of women aged under 31 years will generally decline between 2007 and 2026, with rates increasing for women aged 31 years and over.
The medium paternity variant assumes paternity rates of European or Other men aged under 35 years will generally decline between 2007 and 2026, with rates increasing for men aged 35 years and over. The low paternity variant assumes paternity rates of men of most ages will generally decline between 2007 and 2026. The high paternity variant assumes paternity rates of men aged under 32 years will generally decline between 2007 and 2026, with rates increasing for men aged 32 years and over.
Projected births are reduced to allow for births to European or Other parent(s) that are not registered as European or Other children. The low, medium and high variants assume that 1.6, 2.1 and 2.6 percent, respectively, of births to European or Other parent(s) are non-European and non-Other children.
Mortality
There are three alternative mortality variants – designated low, medium and high – which assume that mortality rates will continue to drop so that the life expectancy at birth for European or Other males will increase to 83.7, 82.2 and 80.7 years, respectively, in 2026. The corresponding life expectancies at birth for European or Other females will be 86.6, 85.4 and 84.3 years in 2026. The medium mortality variant assumes life expectancy at birth in 2007 was 79.1 years for European or Other males and 83.0 years for European or Other females.
Mortality rates are assumed to decrease at different rates at different ages. Between 2007 and 2026, European or Other male mortality rates are assumed to decrease by an average of 2.7, 1.9, and 1.1 percent per year for the low, medium, and high mortality variants, respectively. By comparison, European or Other female mortality rates are assumed to decrease by an average of 2.7, 2.0, and 1.2 percent per year for the low, medium, and high mortality variants, respectively.
Migration
There are three alternative migration variants – designated low, medium and high – which assume long-run annual net migration of European or Other people of -8,000, -3,000 and 2,000, respectively. The medium migration variant assumes net migration of European or Other people of -3,000 in 2007, -9,000 in 2008, -4,000 in 2009, 11,000 in 2010, 5,000 in 2011, and 1,000 in 2012. The low and high migration variants are 5,000 lower and higher, respectively, than the medium variant for each year.
The age-sex patterns of net migration assume the highest net outflows at ages 20–25 years, associated with New Zealanders embarking on overseas travel. The highest net inflows are assumed at ages 28–33 years associated with returning New Zealanders.
Inter-ethnic mobility
There are three alternative inter-ethnic mobility variants – designated low, medium and high – which assume a net change to the European or Other population due to people changing their ethnic identification at an annual rate (in 2007) of 0.2, 0 and -0.2 percent, respectively. The age pattern of inter-ethnic mobility is applied to each sex and assumes the highest net mobility at ages 12–26 years.
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Māori
Fertility
There are three alternative fertility variants – designated low, medium and high – which assume that fertility rates for Māori women will vary until the year 2026 when the total fertility rate will reach 2.20, 2.50 and 2.80 births per woman, respectively. The corresponding total paternity rate of Māori men (with non-Māori women) is assumed to reach 0.80, 0.95 and 1.10 births per man in 2026. The estimated rates in 2005–07 were 2.78 births per Māori woman and 0.97 births per Māori man (with non-Māori women).
The medium fertility variant assumes fertility rates of Māori women aged under 31 years will generally decline between 2007 and 2026, with rates increasing for women aged 31 years and over. The low fertility variant assumes fertility rates of women aged under 34 years will generally decline between 2007 and 2026, with rates increasing for women aged 34 years and over. The high fertility variant assumes fertility rates of women aged under 29 years will generally decline between 2007 and 2026, with rates increasing for women aged 29 years and over.
The medium paternity variant assumes paternity rates of Māori men aged under 35 years will generally decline between 2007 and 2026, with rates increasing for men aged 35 years and over. The low paternity variant assumes paternity rates of men aged under 42 years will generally decline between 2007 and 2026, with rates increasing for men aged 42 years and over. The high paternity variant assumes paternity rates of men aged under 33 years will generally decline between 2007 and 2026, with rates increasing for men aged 33 years and over.
Projected births are reduced to allow for births to Māori parent(s) that are not registered as Māori children. The low, medium and high variants assume that 3.4, 3.9 and 4.4 percent, respectively, of births to Māori parent(s) are non-Māori children.
Mortality
There are three alternative mortality variants – designated low, medium and high – which assume that mortality rates will continue to drop so that the life expectancy at birth for Māori males will increase to 76.9, 75.4 and 73.9 years, respectively, in 2026. The corresponding life expectancies at birth for Māori females will be 80.4, 79.2 and 78.0 years in 2026. The medium mortality variant assumes life expectancy at birth in 2007 was 70.8 years for Māori males and 75.6 years for Māori females.
Mortality rates are assumed to decrease at different rates at different ages. Between 2007 and 2026, Māori male mortality rates are assumed to decrease by an average of 2.6, 2.0, and 1.4 percent per year for the low, medium, and high mortality variants, respectively. By comparison, Māori female mortality rates are assumed to decrease by an average of 2.2, 1.7, and 1.2 percent per year for the low, medium, and high mortality variants, respectively.
Migration
There are three alternative migration variants – designated low, medium and high – which assume long-run annual net migration of Māori people of -4,000, -3,000 and -2,000, respectively. The medium migration variant assumes net migration of Māori people of -4,500 in 2007, -5,500 in 2008, -4,000 in 2009, -2,000 in 2010, and -2,000 in 2011. The low and high variants are 1,000 lower and higher, respectively, than the medium variant for each year.
The age-sex patterns of net migration assume net outflows at all ages, with the highest net outflows at ages 19–26 years.
Inter-ethnic mobility
There are three alternative inter-ethnic mobility variants – designated low, medium and high – which assume a net change to the Māori population due to people changing their ethnic identification at an annual rate (in 2007) of 0, -0.3 and -0.6 percent, respectively. The age pattern of inter-ethnic mobility is applied to each sex and assumes the highest net mobility at ages 12–26 years.
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Asian
Fertility
There are three alternative fertility variants – designated low, medium and high – which assume that fertility rates for Asian women will vary until the year 2026 when the total fertility rate will reach 1.30, 1.50 and 1.70 births per Asian woman, respectively. The corresponding total paternity rate of Asian men (with non-Asian women) is assumed to reach 0.18, 0.23 and 0.28 births per man in 2026. The estimated rates in 2005–07 were 1.52 births per Asian woman and 0.20 births per Asian man (with non-Asian women).
The medium fertility variant assumes fertility rates of Asian women aged under 31 years will generally decline between 2007 and 2026, with rates increasing for women aged 31 years and over. The low fertility variant assumes fertility rates of women aged under 34 years will generally decline between 2007 and 2026, with rates increasing for women aged 34 years and over. The high fertility variant assumes fertility rates of women aged under 28 years will generally decline between 2007 and 2026, with rates increasing for women aged 28 years and over.
The medium paternity variant assumes paternity rates of Asian men aged under 33 years will generally decline between 2007 and 2026, with rates increasing for men aged 33 years and over. The low paternity variant assumes paternity rates of men of most ages will generally decline between 2007 and 2026. The high paternity variant assumes paternity rates of men aged under 31 years will generally decline between 2007 and 2026, with rates increasing for men aged 31 years and over.
Projected births are reduced to allow for births to Asian parent(s) which are not registered as Asian children. The low, medium and high variants assume that 2.9, 3.4 and 3.9 percent, respectively, of births to Asian parent(s) are non-Asian children.
Mortality
There are three alternative mortality variants – designated low, medium and high – which assume that mortality rates will continue to drop so that the life expectancy at birth for Asian males will increase to 88.1, 86.6 and 85.1 years, respectively, in 2026. The corresponding life expectancies at birth for Asian females will be 90.9, 89.7 and 88.5 years in 2026. The medium mortality variant assumes life expectancy at birth in 2007 was 83.7 years for Asian males and 87.3 years for Asian females.
Mortality rates are assumed to decrease at different rates at different ages. Between 2007 and 2026, Asian male mortality rates are assumed to decrease by an average of 2.7, 1.9, and 1.2 percent per year for the low, medium, and high mortality variants, respectively. By comparison, Asian female mortality rates are assumed to decrease by an average of 2.8, 2.1, and 1.4 percent per year for the low, medium, and high mortality variants, respectively.
Migration
There are three alternative migration variants – designated low, medium and high – which assume long-run annual net migration of Asian people of 6,000, 12,000 and 18,000, respectively. The medium migration variant assumes net migration of Asian people of 13,000 in 2007, 15,000 in 2008, and 16,000 in 2009. The low and high variants are 6,000 lower and higher, respectively, than the medium variant for each year.
The age-sex patterns of net migration assume net inflows at most ages, with the highest net inflows at ages 15–22 years partly associated with students arriving for educational purposes.
Inter-ethnic mobility
There are three alternative inter-ethnic mobility variants – designated low, medium and high – which assume a net change to the Asian population due to people changing their ethnic identification at an annual rate (in 2007) of 0, -0.2 and -0.4 percent, respectively. The age pattern of inter-ethnic mobility is applied to each sex and assumes the highest net mobility at ages 12–26 years.
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Pacific
Fertility
There are three alternative fertility variants – designated low, medium and high – which assume that fertility rates for Pacific women will vary until the year 2026 when the total fertility rate will reach 2.35, 2.65 and 2.95 births per Pacific woman, respectively. The corresponding total paternity rate of Pacific men (with non-Pacific women) is assumed to reach 0.85, 1.00 and 1.15 births per man in 2026. The estimated rates in 2005–07 were 2.95 births per Pacific woman and 1.05 births per Pacific man (with non-Pacific women).
The medium fertility variant assumes fertility rates of Pacific women aged under 32 years will generally decline between 2007 and 2026, with rates increasing for women aged 32 years and over. The low fertility variant assumes fertility rates of women aged under 40 years will generally decline between 2007 and 2026, with rates increasing for women aged 40 years and over. The high fertility variant assumes fertility rates of women aged under 29 years will generally decline between 2007 and 2026, with rates increasing for women aged 29 years and over.
The medium paternity variant assumes paternity rates of Pacific men aged under 34 years will generally decline between 2007 and 2026, with rates increasing for men aged 34 years and over. The low paternity variant assumes paternity rates of men aged under 45 years will generally decline between 2007 and 2026, with rates increasing for men aged 45 years and over. The high paternity variant assumes paternity rates of men aged under 31 years will generally decline between 2007 and 2026, with rates increasing for men aged 31 years and over.
Projected births are reduced to allow for births to Pacific parent(s) that are not registered as Pacific children. The low, medium and high variants assume that 2.6, 3.1 and 3.6 percent, respectively, of births to Pacific parent(s) are non-Pacific children.
Mortality
There are three alternative mortality variants – designated low, medium and high – which assume that mortality rates will continue to drop so that the life expectancy at birth for Pacific males will increase to 78.5, 77.0 and 75.5 years, respectively, in 2026. The corresponding life expectancies at birth for Pacific females will be 81.6, 80.4 and 79.3 years in 2026. The medium mortality variant assumes life expectancy at birth in 2007 was 73.3 years for Pacific males and 77.4 years for Pacific females.
Mortality rates are assumed to decrease at different rates at different ages. Between 2007 and 2026, Pacific male mortality rates are assumed to decrease by an average of 2.5, 1.9, and 1.2 percent per year for the low, medium, and high mortality variants, respectively. By comparison, Pacific female mortality rates are assumed to decrease by an average of 2.4, 1.8, and 1.2 percent per year for the low, medium, and high mortality variants, respectively.
Migration
There are three alternative migration variants – designated low, medium and high – which assume long-run annual net migration of Pacific people of 0, 500 and 1,000, respectively. The medium migration variant assumes net migration of Pacific people of 1,000 in 2007. The low and high migration variants are 500 lower and higher, respectively, than the medium variant for each year.
The age-sex patterns of net migration assume the highest net inflows at ages under 20 years and the highest net outflows at ages 22–26 years.
Inter-ethnic mobility
There are three alternative inter-ethnic mobility variants – designated low, medium and high – which assume a net change to the Pacific population due to people changing their ethnic identification at an annual rate (in 2007) of 0, -0.2 and -0.4 percent, respectively. The age pattern of inter-ethnic mobility is applied to each sex and assumes the highest net mobility at ages 12–26 years.
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2006-base to 2026 (released April 2008)
The national ethnic population projections are designed to complement the 2006-base national population projections released in October 2007. However, only mid-range series 6 of the respective ethnic population projections and mid-range series 5 of the New Zealand population projections are designed to be directly comparable. Other series cannot be directly compared because the projection assumptions may be incompatible.
Summary table of assumptions
The projection assumptions for the 'European or Other', Māori, Asian and Pacific populations are summarised in the following table.
 (40 KB)
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European or Other (including New Zealander)
Fertility
There are three alternative fertility variants – designated low, medium and high – which assume that fertility rates for European or Other women will vary until the year 2026 when the total fertility rate will reach 1.55, 1.75 and 1.95 births per woman, respectively. The corresponding total paternity rate of European or Other men (with non-European and non-Other women) is assumed to reach 0.09, 0.14 and 0.19 births per man in 2026. The estimated rates in 2005–07 were 1.92 births per European or Other woman and 0.14 births per European or Other man (with non-European and non-Other women).
The medium fertility variant assumes fertility rates of European or Other women aged under 33 years will generally decline between 2007 and 2026, with rates increasing for women aged 33 years and over. The low fertility variant assumes fertility rates of women aged under 39 years will generally decline between 2007 and 2026, with rates increasing for women aged 39 years and over. The high fertility variant assumes fertility rates of women aged under 31 years will generally decline between 2007 and 2026, but the rates for women aged 31 years and over will increase.
The medium paternity variant assumes paternity rates of European or Other men aged under 34 years will generally decline between 2007 and 2026, with rates increasing for men aged 34 years and over. The low paternity variant assumes paternity rates of men of all ages will decline between 2007 and 2026. By comparison, the high paternity variant assumes paternity rates of men aged under 29 years will generally decline between 2007 and 2026, but the rates for men aged 29 years and over will increase.
Projected births are reduced to allow for births to European or Other parent(s) that are not registered as European or Other children. The low, medium and high variants assume that 1.7, 2.2 and 2.7 percent, respectively, of births to European or Other parent(s) are non-European and non-Other children.
Mortality
There are three alternative mortality variants – designated low, medium and high – which assume that mortality rates will continue to drop so that the life expectancy at birth for European or Other males will increase to 84.1, 82.6 and 81.1 years, respectively, by 2026. The corresponding life expectancies at birth for European or Other females will be 87.4, 86.2 and 85.0 years in 2026. The medium mortality variant assumes life expectancy at birth in 2007 of 79.4 years for European or Other males and 83.2 years for European or Other females.
Mortality rates are assumed to decrease at the same rate at all ages. Between 2007 and 2026, European or Other male mortality rates are assumed to decrease by about 37, 27 and 16 percent for the low, medium and high mortality variants, respectively. By comparison, European or Other female mortality rates are assumed to decrease by about 37, 29 and 19 percent for the low, medium and high mortality variants, respectively.
Migration
There are three alternative migration variants – designated low, medium and high – which assume long-run annual net migration of European or Other people of -8,000, -3,000 and 2,000, respectively. The medium migration variant assumes net migration of European or Other people of -3,000 in 2007, -5,000 in 2008, and -4,000 in 2009. The low and high migration variants are 5,000 lower and higher, respectively, than the medium variant for each year.
The age-sex patterns of net migration assume the highest net outflows at ages 20–25 years, associated with New Zealanders embarking on overseas travel. The highest net inflows are assumed at ages 28–33 years associated with returning New Zealanders.
Inter-ethnic mobility
There are three alternative inter-ethnic mobility variants – designated low, medium and high – which assume a net change to the European or Other population due to people changing their ethnic identification at an annual rate (in 2007) of 0.2, 0 and -0.2 percent, respectively. The age pattern of inter-ethnic mobility is applied to each sex and assumes the highest net mobility at ages 12–26 years.
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Māori
Fertility
There are three alternative fertility variants – designated low, medium and high – which assume that fertility rates for Māori women will vary until the year 2026 when the total fertility rate will reach 2.20, 2.50 and 2.80 births per woman, respectively. The corresponding total paternity rate of Māori men (with non-Māori women) is assumed to reach 0.80, 0.95 and 1.10 births per man in 2026. The estimated rates in 2005–07 were 2.78 births per Māori woman and 0.97 births per Māori man (with non-Māori women).
The medium fertility variant assumes fertility rates of Māori women aged under 31 years will generally decline between 2007 and 2026, with rates increasing for women aged 31 years and over. The low fertility variant assumes fertility rates of women aged under 34 years will generally decline between 2007 and 2026, with rates increasing for women aged 34 years and over. The high fertility variant assumes fertility rates of women aged under 29 years will generally decline between 2007 and 2026, but the rates for women aged 29 years and over will increase.
The medium paternity variant assumes paternity rates of Māori men aged under 35 years will generally decline between 2007 and 2026, with rates increasing for men aged 35 years and over. The low paternity variant assumes paternity rates of men of all ages will decline between 2007 and 2026. By comparison, the high paternity variant assumes paternity rates of men aged under 32 years will generally decline between 2007 and 2026, but the rates for men aged 32 years and over will increase.
Projected births are reduced to allow for births to Māori parent(s) that are not registered as Māori children. The low, medium and high variants assume that 3.5, 4.0 and 4.5 percent, respectively, of births to Māori parent(s) are non-Māori children.
Mortality
There are three alternative mortality variants – designated low, medium and high – which assume that mortality rates will continue to drop so that the life expectancy at birth for Māori males will increase to 78.0, 76.5 and 75.0 years, respectively, by 2026. The corresponding life expectancies at birth for Māori females will be 81.7, 80.6 and 79.4 years in 2026. The medium mortality variant assumes life expectancy at birth in 2007 of 70.4 years for Māori males and 75.2 years for Māori females.
Mortality rates are assumed to decrease at the same rate at all ages. Between 2007 and 2026, Māori male mortality rates are assumed to decrease by about 45, 39 and 31 percent for the low, medium and high mortality variants, respectively. By comparison, Māori female mortality rates are assumed to decrease by about 43, 37 and 31 percent for the low, medium and high mortality variants, respectively.
Migration
There are three alternative migration variants – designated low, medium and high – which assume long-run annual net migration of Māori people of -4,000, -3,000 and -2,000, respectively. The medium migration variant assumes net migration of Māori people of -4,500 in 2007, -5,000 in 2008, and -4,000 in 2009. The low and high variants are 1,000 lower and higher, respectively, than the medium variant for each year.
The age-sex patterns of net migration assume net outflows at all ages, with the highest net outflows at ages 19–26 years.
Inter-ethnic mobility
There are three alternative inter-ethnic mobility variants – designated low, medium and high – which assume a net change to the Māori population due to people changing their ethnic identification at an annual rate (in 2007) of 0, -0.3 and -0.6 percent, respectively. The age pattern of inter-ethnic mobility is applied to each sex and assumes the highest net mobility at ages 12–26 years.
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Asian
Fertility
There are three alternative fertility variants – designated low, medium and high – which assume that fertility rates for Asian women will vary until the year 2026 when the total fertility rate will reach 1.35, 1.55 and 1.75 births per Asian woman, respectively. The corresponding total paternity rate of Asian men (with non-Asian women) is assumed to reach 0.17, 0.22 and 0.27 births per man in 2026. The estimated rates in 2005–07 were 1.52 births per Asian woman and 0.20 births per Asian man (with non-Asian women).
The medium fertility variant assumes fertility rates of Asian women aged under 30 years will generally decline between 2007 and 2026, with rates increasing for women aged 30 years and over. The low fertility variant assumes fertility rates of women aged under 34 years will generally decline between 2007 and 2026, with rates increasing for women aged 34 years and over. The high fertility variant assumes fertility rates of women aged under 27 years will generally decline between 2007 and 2026, but the rates for women aged 27 years and over will increase.
The medium paternity variant assumes paternity rates of Asian men aged under 32 years will generally decline between 2007 and 2026, with rates increasing for men aged 32 years and over. The low paternity variant assumes paternity rates of men aged under 38 years will generally decline between 2007 and 2026, but the rates for men aged 38 years and over will increase. The high paternity variant assumes paternity rates of men aged under 27 years will generally decline between 2007 and 2026, but the rates for men aged 27 years and over will increase.
Projected births are reduced to allow for births to Asian parent(s) which are not registered as Asian children. The low, medium and high variants assume that 3.1, 3.6 and 4.1 percent, respectively, of births to Asian parent(s) are non-Asian children.
Mortality
There are three alternative mortality variants – designated low, medium and high – which assume that mortality rates will continue to drop so that the life expectancy at birth for Asian males will increase to 86.9, 85.4 and 84.0 years, respectively, by 2026. The corresponding life expectancies at birth for Asian females will be 90.0, 88.8 and 87.6 years in 2026. The medium mortality variant assumes life expectancy at birth in 2007 of 84.0 years for Asian males and 87.2 years for Asian females.
Mortality rates are assumed to decrease at the same rate at all ages. Between 2007 and 2026, Asian male mortality rates are assumed to decrease by about 25, 14 and 1 percent for the low, medium and high mortality variants, respectively. By comparison, Asian female mortality rates are assumed to decrease by about 26, 16 and 5 percent for the low, medium and high mortality variants, respectively.
Migration
There are three alternative migration variants – designated low, medium and high – which assume long-run annual net migration of Asian people of 6,000, 12,000 and 18,000, respectively. The medium migration variant assumes net migration of Asian people of 13,000 in 2007, 2008 and 2009. The low and high variants are 6,000 lower and higher, respectively, than the medium variant for each year.
The age-sex patterns of net migration assume net inflows at most ages, with the highest net inflows at ages 15–21 years partly associated with students arriving for educational purposes.
Inter-ethnic mobility
There are three alternative inter-ethnic mobility variants – designated low, medium and high – which assume a net change to the Asian population due to people changing their ethnic identification at an annual rate (in 2007) of 0, -0.2 and -0.4 percent, respectively. The age pattern of inter-ethnic mobility is applied to each sex and assumes the highest net mobility at ages 12–26 years.
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Pacific
Fertility
There are three alternative fertility variants – designated low, medium and high – which assume that fertility rates for Pacific women will vary until the year 2026 when the total fertility rate will reach 2.30, 2.60 and 2.90 births per Pacific woman, respectively. The corresponding total paternity rate of Pacific men (with non-Pacific women) is assumed to reach 0.90, 1.05 and 1.20 births per man in 2026. The estimated rates in 2005–07 were 2.95 births per Pacific woman and 1.05 births per Pacific man (with non-Pacific women).
The medium fertility variant assumes fertility rates of Pacific women aged under 32 years will generally decline between 2007 and 2026, with rates increasing for women aged 32 years and over. By comparison, the low fertility variant assumes fertility rates of women of most ages will generally decline between 2007 and 2026. The high fertility variant assumes fertility rates of women aged under 30 years will generally decline between 2007 and 2026, but the rates for women aged 30 years and over will increase.
The medium paternity variant assumes paternity rates of Pacific men aged under 34 years will generally decline between 2007 and 2026, with rates increasing slightly for men aged 34 years and over. The low paternity variant assumes paternity rates of men aged under 46 years will generally decline between 2007 and 2026, but the rates for men aged 46 years and over will increase. The high paternity variant assumes paternity rates of men aged under 31 years will generally decline between 2007 and 2026, but the rates for men aged 31 years and over will increase.
Projected births are reduced to allow for births to Pacific parent(s) that are not registered as Pacific children. The low, medium and high variants assume that 2.8, 3.3 and 3.8 percent, respectively, of births to Pacific parent(s) are non-Pacific children.
Mortality
There are three alternative mortality variants – designated low, medium and high – which assume that mortality rates will continue to drop so that the life expectancy at birth for Pacific males will increase to 79.9, 78.4 and 76.9 years, respectively, by 2026. The corresponding life expectancies at birth for Pacific females will be 83.5, 82.3 and 81.1 years in 2026. The medium mortality variant assumes life expectancy at birth in 2007 of 72.8 years for Pacific males and 77.2 years for Pacific females.
Mortality rates are assumed to decrease at the same rate at all ages. Between 2007 and 2026, Pacific male mortality rates are assumed to decrease by about 44, 37 and 29 percent for the low, medium and high mortality variants, respectively. By comparison, Pacific female mortality rates are assumed to decrease by about 43, 37 and 30 percent for the low, medium and high mortality variants, respectively.
Migration
There are three alternative migration variants – designated low, medium and high – which assume long-run annual net migration of Pacific people of 0, 500 and 1,000, respectively. The medium migration variant assumes net migration of Pacific people of 1,000 in 2007. The low and high migration variants are 500 lower and higher, respectively, than the medium variant for each year.
The age-sex patterns of net migration assume the highest net inflows at ages under 20 years and the highest net outflows at ages 22–25 years.
Inter-ethnic mobility
There are three alternative inter-ethnic mobility variants – designated low, medium and high – which assume a net change to the Pacific population due to people changing their ethnic identification at an annual rate (in 2007) of 0, -0.2 and -0.4 percent, respectively. The age pattern of inter-ethnic mobility is applied to each sex and assumes the highest net mobility at ages 12–26 years.
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National Family and Household Projections
National family and household projections 2006(base)–2031 update were released via Hot Off the Press (ISSN 1179-2175) on 19 July 2010. They are derived from the 2009-base national population projections released on 27 October 2009. The latest family and household projections supersede those released via Hot Off the Press (ISSN 1178-0584) in December 2008 which were derived from the 2006-base national population projections released in October 2007.
The national family and household projections are designed to complement the 2009-base national population projections released in October 2009. However, only mid-range series 5B has been formulated to produce demographically plausible results by assessing both observed trends between 1986 and 2006, and likely future trends to 2031. Other series may project significantly different numbers of male and female partners in 'couple without children' and/or 'two-parent' families, because the living arrangement type rate variant A are formulated solely from observed historical rates.
The reference report New Zealand Family and Household Projections (2001(base)–2021) released in June 2004 contains detailed information on methods and assumptions. Although these projections have been superseded by more recent projections, the general trends and features presented in the report are still relevant.
Family and household concepts
These projections are based on the definitions of family and household used in the 2006 Census of Population and Dwellings. A family is defined as a couple, with or without children, or one parent with children, usually living together in a household. A household is defined as one person usually living alone, or two or more people usually living together and sharing facilities (for example, eating facilities, cooking facilities, bathroom and toilet facilities, a living area) in a private dwelling. No information is available from the census on families and households extending beyond a single dwelling, or on families defined using different concepts (for example, whanau), and minimal information is available on families in non-private dwellings.
In these family and household projections, all people are allocated to one of 11 living arrangement types. The living arrangement type refers to the usual family and household role of a person based on a combination of individual, family, household and dwelling information from the census. The projections are based on allocating people to one role from several broad roles they may have within each social structure. These roles vary by age and sex, and are assumed to change over time with changes in social patterns.
The projections do not give a complete picture of the complexity of family and household structures, because people can and do have more than one living arrangement type role in any one entity, and families and households are not necessarily synonymous. Although people can have more than one residence, their living arrangement type role is generally based on the family and household structure of where they usually live, as self-identified by them in the census. Because households are defined as discrete units, the fluidity of living arrangements where people are associated with more than one household for study, work or shared-care purposes is not addressed.
Opposite-sex and same-sex couples are not projected separately, but are included in projections of 'couple without children' and 'two-parent' families.
It is also important to note that the definitions of parents and children are social, not biological. For example, parents include people aged 15 years or over usually living with at least one of their natural, step-, adopted or foster children (who is not usually living with a partner or child of their own). Similarly, a child is a person of any age usually living with one or two natural, step- or adopted parents (but not usually living with a partner or child of their own). No information is available on the strength of identified parent-child relationships in terms of emotional and/or financial support.
Base population
These projections have as a base the estimated resident population of New Zealand at 30 June 2006. This population (4.185 million) was based on the census usually resident population count (4.028 million) at 7 March 2006 with adjustments for:
1. net census undercount (+80,000)
2. residents temporarily overseas on census night (+64,000)
3. births, deaths and net migration between census night (7 March 2006) and 30 June 2006 (+9,000)
4. reconciliation with demographic estimates at ages 0–4 years (+3,000).
For more information about the base population, refer to Population Estimates.
The estimated numbers of families and households are derived indirectly from the estimated resident population and the estimated living arrangement type rates for each age-sex group. The estimated number of families (1.168 million) and households (1.553 million) are equivalent to the census family count (1.068 million) and census household count (1.454 million), respectively, at 7 March 2006, with adjustments for:
1. net census undercount
2. families and households temporarily overseas on census night
3. change between census night (7 March 2006) and 30 June 2006
4. families and households temporarily absent within New Zealand.
Method
The cohort component method has been used to derive the population projections. In this method, the base population is projected forward by calculating the effect of deaths and migration within each age-sex group according to specified mortality and migration assumptions. New birth cohorts are generated by applying specified fertility assumptions to the female population of childbearing age.
The propensity method has subsequently been used to derive the family and household projections. In this method, living arrangement type rates (or propensities) are applied to population projections to give projections of the population in different living arrangement types. These projections are subsequently aggregated to give projections of families (by broad family type) and households (by broad household type).
The number of couple without children families = (male partners in couple-without-children families + female partners in couple-without-children families) ÷ 2.
The number of two-parent families = (male partners/parents in two-parent families + female partners/parents in two-parent families) ÷ 2.
The number of one-parent families = male parents in one-parent families + female parents in one-parent families.
The number of family households = number of families ÷ average number of families per family household.
The number of one-person households = number of people in one-person households.
The number of other multi-person households = number of people in other multi-person households ÷ average number of people per other multi-person household.
2006-base to 2031 update (released July 2010)
Alternative series
Six alternative series have been produced by combining three population projection series with three variants of living arrangement type rates. The three population projection series are:
- series 1 which assumes low fertility, high mortality, and low migration
- series 5 which assumes medium fertility, medium mortality, and medium migration
- series 9 which assumes high fertility, low mortality, and high migration.
Each family and household projection series is denoted by the population projection series and variant of living arrangement type rates. For example, series 5B denotes that variant 'B' living arrangement type rates have been applied to population projection series 5.
At the time of release, projection series 5B is considered the most suitable for assessing future family and household changes. Moreover, only series 5B has been formulated to produce demographically plausible results, by assessing both observed trends between 1986 and 2006 and likely future trends to 2031. Other series may project significantly different numbers of male and female partners in couple-without-children and/or two-parent families, because the living arrangement type rate A variants are formulated solely from observed historical rates.
The other projection series allow users to assess the impact on the number of families and households resulting from different population and/or living arrangement type scenarios. For example, series 1B, 5B, and 9B can be used for assessing the effect of different population outcomes combined with variant B living arrangement type rates; and series 5A and 5B illustrate the effect of different living arrangement type assumptions combined with the mid-range population scenario.
Fertility
There are three alternative fertility variants – designated low, medium, and high – which assume that fertility rates will vary until the year 2026 when the total fertility rate will reach 1.70, 1.90, and 2.10 births per woman, respectively. After 2026, fertility rates are assumed to stay constant. The total fertility rate in the year ended June 2009 was 2.14 births per woman (based on births by date of registration).
The medium fertility variant assumes fertility rates of women aged under 32 years will decline between 2009 and 2026, but increase for women aged 32 years and over. By comparison, the low fertility variant assumes fertility rates will decrease between 2009 and 2026 at most ages. The high fertility variant assumes that fertility rates of women aged under 32 years will drop between 2009 and 2026, but increase for women aged 32 years and over.
A sex ratio at birth of 105.5 males per 100 females is assumed, based on the historical annual average of the New Zealand population.
Mortality
There are three alternative mortality variants – designated low, medium, and high – which assume that mortality rates will continue to drop so that the period life expectancy at birth for males will increase to 83.6, 82.1, and 80.6 years, respectively, by 2031. The corresponding life expectancies for females in 2031 will be 86.6, 85.3, and 84.1 years. The life expectancy at birth in 2005–07, from complete period life tables, was 78.0 years for males and 82.2 years for females.
Mortality rates are assumed to decrease at different rates at different ages. Between 2006 and 2031, male mortality rates are assumed to decrease by an average of 2.2, 1.6, and 1.0 percent per year for the low, medium, and high mortality variants, respectively. By comparison, female mortality rates are assumed to decrease by an average of 2.2, 1.7, and 1.1 percent per year for the low, medium, and high mortality variants, respectively.
Migration
There are three alternative migration variants – designated low, medium, and high – which assume long-run annual net migration of 5,000, 10,000, and 15,000, respectively. The medium migration variant assumes net migration of 25,000 in 2010, 19,000 in 2011, and 14,000 in 2012. The low and high migration variants are 5,000 lower and higher, respectively, than the medium variant for each year. These levels are based on an analysis of immigration permits, residence applications and approvals, overseas student numbers, and arrivals and departures analysed by characteristics such as citizenship, country of last/next permanent residence, and age.
Consistent with historical and recent trends, the age-sex patterns of net migration assume the main net outflow at ages 22–25 years, mainly due to young New Zealanders embarking on overseas travel and the departure of overseas students. Net inflows are assumed for most other ages with the highest net inflows at 15–20 and 27–37 years.
Living arrangement type rates (LATRs)
There are two alternative LATR variants – designated A and B. Variant A assumes that LATRs will remain constant at 2006 levels. Variant B assumes that LATRs will change linearly between 2006 and 2031, based on an assessment of observed trends between 1986 and 2006 and likely future trends, by sex and single-year of age.
Variant B is the preferred variant, because it has been formulated to produce demographically plausible results. For variant B, the main changes in LATRs assumed between 2006 and 2031 are:
- Partner in couple-without-children family: Increasing rates for males and females at most ages, especially at ages 30–59 years for males, and 25–54 and 70–79 years for females. This reflects lower fertility rates with fewer couples having children, and a slight convergence of male life expectancy to female life expectancy with more couples having both partners living to older ages.
- Partner/parent in two-parent family: Decreasing rates for males and females at most ages, especially at ages 25–64 years for males and 25–54 years for females. This reflects lower fertility rates with fewer couples having children.
- Child in two-parent family: Decreasing rates at most ages, especially at ages 0–24 years. This reflects increased rates of single parenting from separation, divorce, childbearing outside couple relationships, and more complex shared-care arrangements.
- Parent in one-parent family: Increasing rates at most ages. This reflects increased rates of single parenting.
- Child in one-parent family: Increasing rates at most ages, especially at ages 0–24 years. This reflects increased rates of single parenting.
- Person in other multi-person household: Increasing rates at most ages, especially 15–24 years, which is associated with higher numbers of students.
- Person in one-person household: Increasing rates at most ages, especially 30–94 years for males. These increases are associated with increased rates of marriage dissolution, decreasing rates of people forming partnerships, and lower fertility rates. The proportion of females aged 45–79 years living alone is assumed to drop slightly, given a slight convergence of male life expectancy to female life expectancy.
- Person in non-private dwelling: Increasing rates at ages 15–24 years, associated with higher numbers of students. Decreasing rates at older ages, associated with increasing life expectancy and declines in morbidity rates.
For variants A and B, the following factors remain constant at the 2006 levels:
- the average number of families per family household is assumed to remain constant at 1.041
- the average number of people per other multi-person household is assumed to remain constant at 2.600
- the proportion of two-parent families with dependent children is assumed to remain constant at 0.832
- the proportion of one-parent families with dependent children is assumed to remain constant at 0.754.
2006-base to 2031 (released December 2008)
Alternative series
Six alternative series have been produced by combining three population projection series with three variants of living arrangement type rates. The three population projection series are:
- series 1 which assumes low fertility, high mortality and low migration
- series 5 which assumes medium fertility, medium mortality and medium migration
- series 9 which assumes high fertility, low mortality and high migration.
Each family and household projection series is denoted by the population projection series and variant of living arrangement type rates. For example, series 5B denotes that variant 'B' living arrangement type rates have been applied to population projection series 5.
At the time of release, projection series 5B is considered the most suitable for assessing future family and household changes. Moreover, only series 5B has been formulated to produce demographically plausible results by assessing both observed trends between 1986 and 2006, and likely future trends to 2031. Other series may project significantly different numbers of male and female partners in couple-without-children and/or two-parent families, because the living arrangement type rate variants A are formulated solely from observed historical rates.
The other projection series allow users to assess the impact on the number of families and households resulting from different population and/or living arrangement type scenarios. For example, series 1B, 5B and 9B can be used for assessing the effect of different population outcomes combined with variant B living arrangement type rates; and series 5A and 5B illustrate the effect of different living arrangement type assumptions combined with the mid-range population scenario.
Fertility
There are three alternative fertility variants – designated low, medium and high – which assume that fertility rates will vary until the year 2026 when the total fertility rate will reach 1.70, 1.90 and 2.10 births per woman, respectively. After 2026, fertility rates are assumed to stay constant. The base total fertility rate in 2006 was 1.99 births per woman (based on estimated births by date of occurrence).
The medium fertility variant assumes fertility rates of women aged under 32 years will decline between 2006 and 2026, while rates for women aged 32 years and over will increase. By comparison, the low fertility variant assumes fertility rates will decrease between 2006 and 2026 for most ages. The high fertility variant assumes that fertility rates will drop between 2006 and 2026 for women aged under 31 years and increase for women aged 31 years and over.
A sex ratio at birth of 105.5 males per 100 females is assumed, based on the historical annual average.
Mortality
There are three alternative mortality variants – designated low, medium and high – which assume that mortality rates will continue to drop so that life expectancy at birth will increase to 84.3, 82.5 and 80.8 years for males, respectively, by 2031. The corresponding life expectancies for females in 2031 will be 87.6, 86.2 and 84.8 years. The base life expectancy at birth in 2005–07 was 78.2 years for males and 82.2 years for females.
Mortality rates are assumed to decrease at the same rate at all ages. Between 2006 and 2031, male mortality rates are assumed to decrease by about 42, 32 and 21 percent for the low, medium and high mortality variants, respectively. By comparison, female mortality rates are assumed to decrease by about 41, 32 and 22 percent for the low, medium and high mortality variants, respectively.
Migration
There are three alternative migration variants – designated low, medium and high – which assume long-run annual net migration levels of 5,000, 10,000 and 15,000, respectively. Short-run migration levels converging to the long-run levels are assumed for 2007–09. These short-run levels are based on an analysis of immigration permits, residence applications and approvals, overseas student numbers, and arrivals and departures analysed by characteristics such as citizenship, country of last/next permanent residence and age.
Consistent with historical and recent trends, the age-sex patterns of net migration assume the main net outflow at ages 21–25 years, mainly due to young New Zealanders embarking on overseas travel and the departure of students from overseas after studying in New Zealand. Net inflows are assumed for most other ages, with the highest net inflows at 15–19 and 27–38 years.
Living arrangement type rates (LATRs)
There are two alternative LATR variants – designated A and B. Variant A assumes that LATRs will remain constant at 2006 levels. Variant B assumes that LATRs will change linearly between 2006 and 2031 based on an assessment of observed trends between 1986 and 2006, and likely future trends, by sex and single-year of age.
Variant B is the preferred variant, because it has been formulated to produce demographically plausible results. For variant B, the main changes in LATRs assumed between 2006 and 2031 are:
1. Partner in couple-without-children family: Increasing rates for males and females at most ages, especially at ages 30–54 years for males, and 25–54 and 70–84 years for females. This reflects lower fertility rates with fewer couples having children, and a slight convergence of male life expectancy to female life expectancy with more couples having both partners living to older ages.
2. Partner/parent in two-parent family: Decreasing rates for males and females at most ages, especially at ages 25–64 years for males and 25–59 years for females. This reflects lower fertility rates with fewer couples having children.
3. Child in two-parent family: Decreasing rates at most ages, especially at ages 0–19 years. This reflects increased rates of single parenting from separation, divorce, childbearing outside of couple relationships, and more complex shared care arrangements.
4. Parent in one-parent family: Increasing rates at most ages, especially at ages 30–45 years. This reflects increased rates of single parenting.
5. Child in one-parent family: Increasing rates at most ages, especially at ages 0–19 years. This reflects increased rates of single parenting.
6. Person in other multi-person household: Increasing rates at most ages, especially 15–24 years associated with higher numbers of students.
7. Person in one-person household: Increasing rates at most ages, especially 30–89 years for males and 35–54 years for females. These increases are associated with increased rates of marriage dissolution, decreasing rates of people forming partnerships, and lower fertility rates. The proportion of females aged 60–79 years living alone is assumed to drop slightly, given a slight convergence of male life expectancy to female life expectancy.
8. Person in non-private dwelling: Increasing rates at ages 15–24 years associated with higher numbers of students. Decreasing rates at ages 85+ years associated with increasing life expectancy and declines in morbidity rates.
For variants A and B, the following factors remain constant at the 2006 levels:
- the average number of families per family household is assumed to remain constant at 1.041 from 2006–31
- the average number of people per other multi-person household is assumed to remain constant at 2.600 from 2006–31
- the proportion of two-parent families with dependent children is assumed to remain constant at 0.832 from 2006–31
- the proportion of one-parent families with dependent children is assumed to remain constant at 0.754 from 2006–31.
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National Labour Force Projections
National labour force projections 2006(base)–2061 update were released via Hot Off the Press (ISSN 1178-0606) on 25 May 2010. They are derived from the 2009-base national population projections released on 27 October 2009. The latest labour force projections supersede those released via Hot Off the Press (ISSN 1178-0606) in May 2008 which were derived from the 2006-base national population projections released in October 2007.
Labour force projections indicate the future supply of people, usually living in New Zealand, available for work. However, they do not indicate the extent to which people are available (eg number of hours per week). Labour force projections are derived from population projections by multiplying the projected population by the assumed labour force participation rates (LFPRs), by single year of age and sex. The labour force comprises people aged 15 years and over who regularly work for one or more hours per week for financial gain, or work without pay in a family business, or are unemployed and actively seeking part-time or full-time work.
Base population
These labour force projections have as a base the estimated resident population of New Zealand in the labour force at 30 June 2006. The estimated resident population (4.185 million) was derived from the census usually resident population count (4.028 million) at 7 March 2006 with adjustments for:
- net census undercount (+80,000)
- residents temporarily overseas on census night (+64,000)
- births, deaths and net migration between census night (7 March 2006) and 30 June 2006 (+9,000)
- reconciliation with demographic estimates at ages 0–4 years (+3,000).
The estimated and projected population and labour force are not directly comparable with census counts because of these adjustments. For more information about the base population, refer to Population Estimates.
The estimated resident population in the labour force at 30 June 2006 was derived by applying the estimated LFPRs to the estimated resident population, by single year of age and sex. The estimated LFPRs at 30 June 2006 were derived from an assessment of both HLFS and 2006 Census data. The projections use the same labour force definition as these two data sources, although there are important differences between the two data sources:
- The HLFS provides the official measure of the labour force using an interviewer-administered survey of about 15,000 households and 30,000 people each quarter. By comparison, the census provides a snapshot of the labour force every five years.
- The HLFS measures labour force status over each quarter, while the census question refers to labour force status in the week before the census date.
- Unlike the HLFS, the census is not subject to sample error (although both data sources may contain non-sampling errors). As a result, the census can provide information at a more detailed demographic level (eg single year of age) than the HLFS.
- Non-response in the HLFS is minimised through the use of best survey practices. Because the census is self-administered, higher rates of non-response occur.
- The HLFS generally excludes people in the armed forces and non-private dwellings (eg retirement homes, hospitals, prisons), while the census includes everyone who is in New Zealand on census night.
Compared with the HLFS, the 2006 Census generally indicated higher male LFPRs under 25 years and over 60 years, and higher female LFPRs at most ages. The 2006 Census also generally indicated lower male LFPRs in the main working ages (25–59 years).
2006-base to 2061 update (released May 2010)
National labour force projections 2006(base)–2061update were released via Hot Off the Press (ISSN 1178-0606) on 25 May 2010. They are derived from the 2009-base national population projections released on 27 October 2009.
Alternative series
Nine alternative series of labour force projections have been produced from combinations of three population series (series 1, 5 and 9) and three variants of labour force participation rates (low, medium and high). Each labour force projection series is denoted by the population projection series and variant of labour force participation rates. For example, series 5M denotes that medium variant labour force participation rates have been applied to population projection series 5.
At the time of release, projection series 5M is considered the most suitable for assessing future labour force changes. The other projection series allow users to assess the impact on the labour force size and structure resulting from different population and/or labour force participation scenarios. For example, series 1M, 5M and 9M can be used for assessing the effect of different population outcomes combined with the medium variant LFPRs; and series 5L, 5M and 5H illustrate the effect of different LFPR assumptions combined with the mid-range population scenario.
Method
The cohort component method was used to derive the population projections. By this method, the base population is projected forward by calculating the effects of deaths and migration within each age-sex group according to specified mortality and migration assumptions. New birth cohorts are generated by applying specified fertility assumptions to the female population of childbearing age.
The labour force projections were subsequently derived by multiplying the projected population by the assumed labour force participation rates, by single year of age and sex.
Fertility
The 2009-base national population projections adopted three alternative fertility variants – designated low, medium and high – which assume that fertility rates will vary until the year 2026 when the total fertility rate will reach 1.70, 1.90 and 2.10 births per woman, respectively. After 2026, fertility rates are assumed to stay constant. The base total fertility rate in the year ended June 2009 was 2.14 births per woman (based on estimated births by date of occurrence).
The medium fertility variant assumes fertility rates of women aged under 32 years will decline between 2009 and 2026, but increase for women aged 32 years and over. By comparison, the low fertility variant assumes fertility rates will decrease between 2009 and 2026 for most ages. The high fertility variant assumes that fertility rates of women aged less than 32 years will drop between 2009 and 2026, but increase for women aged 32 years and over.
A sex ratio at birth of 105.5 males per 100 females is assumed, based on the historical annual average of the New Zealand population.
Mortality
The 2009-base national population projections adopted three alternative mortality variants – designated low, medium and high – which assume that mortality rates will continue to drop so that life expectancy at birth for males will increase to 88.6, 85.6 and 82.6 years for males, respectively, by 2061. The corresponding life expectancies for females in 2061 will be 91.2, 88.7 and 86.2 years. The base life expectancy at birth in 2005–07, from the complete life tables, was 78.0 years for males and 82.2 years for females.
Mortality rates are assumed to decrease at different rates at different ages. Between 2006 and 2061, male mortality rates are assumed to decrease by an average 2.1, 1.6 and 1.0 percent per year for the low, medium and high mortality variants, respectively. By comparison, female mortality rates are assumed to decrease by an average 2.4, 1.8 and 1.3 percent per year for the low, medium and high mortality variants, respectively.
Migration
The 2009-base national population projections adopted three alternative migration variants – designated low, medium and high – which assume long-range annual net migration levels of 5,000, 10,000 and 15,000, respectively. The medium migration variant assumes net migration of 25,000 in 2010, 19,000 in 2011, and 14,000 in 2012. The low and high migration variants are 5,000 lower and higher, respectively, than the medium variant for each year. These levels are based on an analysis of immigration permits, residence applications and approvals, overseas student numbers, and arrivals and departures analysed by characteristics such as citizenship, country of last/next permanent residence, and age.
Consistent with historical and recent trends, the age-sex patterns of net migration assume the main net outflow at ages 22–25 years, mainly due to young New Zealanders embarking on overseas travel and the departure of overseas students. Net inflows are assumed for most other ages with the highest net inflows at ages 15–20 and 27–37 years.
Labour force participation
There are three alternative labour force participation variants – designated low, medium, and high – which assume that LFPRs will vary until 2051, when the average working life (to age 80 years) for males will be 45.8, 48.3 and 50.8 years, respectively. The corresponding average working life (to age 80 years) for females will be 38.8, 40.9 and 43.0 years. The base average working life (to age 80 years) in 2006 was 45.3 years for males and 36.9 years for females.
Labour force participation assumptions are based on an assessment of recent trends in HLFS and census data. LFPRs are assumed to change annually between 2006 and 2051. For the medium variant, the main change assumed between 2006 and 2051 is for LFPRs to increase significantly for males and females aged 55 years and over. This reflects increasing flexibility in the age of retirement, with no compulsory age of retirement, and increasing life expectancy.
For males, LFPRs are assumed to remain constant at 2006 levels for those aged 15–19 years. LFPRs of those aged 20–24 are assumed to decrease slightly between 2006 and 2011, and then remain constant. LFPRs of those aged 25–54 years are assumed to decrease slightly between 2006 and 2011, then increase slightly to 2016, then remain constant.
For females, LFPRs for those aged 15–19 years are assumed to decrease slightly between 2006 and 2011, and then remain constant. For those aged 20–24 years, LFPRs are assumed to increase slightly between 2006 and 2011, and then remain constant. LFPRs of those aged 25–54 are assumed to increase between 2006 and 2016, and then remain constant.
The low and high variants assume LFPRs that are lower and higher, respectively, than the medium variant at all ages.
2006-base to 2061 (released May 2008)
National labour force projections 2006(base)–2061 were released via Hot Off the Press (ISSN 1178-0606) in May 2008. They are derived from the 2006-base national population projections released in October 2007. These have been superseded by the national labour force projections 2006-base update that were released via Hot Off the Press (ISSN 1178-0606) on 25 May 2010.
Alternative series
Nine alternative series of labour force projections have been produced from combinations of three population series (series 1, 5 and 9) and three variants of labour force participation rates (low, medium and high). Each labour force projection series is denoted by the population projection series and variant of labour force participation rates. For example, series 5M denotes that medium variant labour force participation rates have been applied to population projection series 5.
At the time of release, projection series 5M is considered the most suitable for assessing future labour force changes. The other projection series allow users to assess the impact on the labour force size and structure resulting from different population and/or labour force participation scenarios. For example, series 1M, 5M and 9M can be used for assessing the effect of different population outcomes combined with the medium variant LFPRs; and series 5L, 5M and 5H illustrate the effect of different LFPR assumptions combined with the mid-range population scenario.
Method
The cohort component method was used to derive the population projections. By this method, the base population is projected forward by calculating the effects of deaths and migration within each age-sex group according to specified mortality and migration assumptions. New birth cohorts are generated by applying specified fertility assumptions to the female population of childbearing age.
The labour force projections were subsequently derived by multiplying the projected population by the assumed labour force participation rates, by single year of age and sex.
Fertility
The 2006-base national population projections adopted three alternative fertility variants – designated low, medium and high – which assume that fertility rates will vary until the year 2026 when the total fertility rate will reach 1.70, 1.90 and 2.10 births per woman, respectively. After 2026, fertility rates are assumed to stay constant. The base total fertility rate in 2006 was 1.99 births per woman (based on estimated births by date of occurrence).
The medium fertility variant assumes fertility rates of women aged under 32 years will decline between 2006 and 2026, while rates for women aged 32 years and over will increase. By comparison, the low fertility variant assumes fertility rates will decrease between 2006 and 2026 for most ages. The high fertility variant assumes that fertility rates will drop between 2006 and 2026 for women aged under 31 years and increase for women aged 31 years and over.
A sex ratio at birth of 105.5 males per 100 females is assumed, based on the historical annual average.
Mortality
The 2006-base national population projections adopted three alternative mortality variants – designated low, medium and high – which assume that mortality rates will continue to drop so that life expectancy at birth for males will increase to 87.0, 84.5 and 82.0 years for males, respectively, by 2061. The corresponding life expectancies for females in 2061 will be 90.0, 88.0 and 86.0 years. The base life expectancy at birth in 2005–07 was 78.2 years for males and 82.2 years for females.
Mortality rates are assumed to decrease at the same rate at all ages. Between 2006 and 2061, male mortality rates are assumed to decrease by about 55, 44 and 29 percent for the low, medium and high mortality variants, respectively. By comparison, female mortality rates are assumed to decrease by about 53, 44 and 31 percent for the low, medium and high mortality variants, respectively.
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Migration
The 2006-base national population projections adopted three alternative migration variants – designated low, medium and high – which assume long-run annual net migration levels of 5,000, 10,000 and 15,000, respectively. Short-run migration levels converging to the long-run levels are assumed for 2007–09. These short-run levels are based on an analysis of immigration permits, residence applications and approvals, overseas student numbers, and arrivals and departures analysed by characteristics such as citizenship, country of last/next permanent residence and age.
Consistent with historical and recent trends, the age-sex patterns of net migration assume the main net outflow at ages 21–25 years, mainly due to young New Zealanders embarking on overseas travel and the departure of students from overseas after studying in New Zealand. Net inflows are assumed for most other ages, with the highest net inflows at ages 15–19 and 27–38 years.
Labour force participation
There are three alternative labour force participation variants – designated low, medium and high – which assume that LFPRs will vary until 2016, when the average working life (to age 80 years) for males will be 45.1, 47.0 and 49.0 years, respectively. The corresponding average working life (to age 80 years) for females will be 37.6, 39.2 and 40.8 years. The base average working life (to age 80 years) in 2006 was 45.3 years for males and 36.9 years for females.
Labour force participation assumptions are based on an assessment of recent trends in HLFS and census data. LFPRs are assumed to change annually at a decreasing rate between 2006 and 2016. Most change occurs between 2006 and 2011, with the change between 2011 and 2016 being about one-quarter of that assumed for 2006–16. After 2016, LFPRs are assumed to stay constant.
For the medium variant, the main change assumed between 2006 and 2016 is for LFPRs to increase significantly for males and females aged 55 years and over. This reflects increasing flexibility in the age of retirement, with no compulsory age of retirement, and increasing life expectancy. For males, LFPRs are assumed to have no changes under 50 years. For females, LFPRs are assumed to have no changes for those aged 15-19 years, but increase slightly for those aged 20–54 years.
The low and high variants assume LFPRs that are lower and higher, respectively, than the medium variant at all ages.
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Subnational Population Projections
Projections (2006-base to 2031 update at five-year intervals) of the population usually living in the 16 regional council areas and 73 territorial authority areas (cities and districts) of New Zealand were released via Hot Off the Presson 24 February 2010. These supersede the subnational population projections 2006-base released via Hot Off the Press(ISSN 1178-0681 ) on 3 December 2007.
Base population
These projections have as a base the estimated resident population of each area at 30 June 2006. This population was based on the census usually resident population count of each area at 7 March 2006 with adjustments for:
- net census undercount
- residents temporarily overseas on census night
- births, deaths, and net migration between census night (7 March 2006) and 30 June 2006
- reconciliation with demographic estimates at ages 0–4 years.
For more information about the base population, refer to Population Estimates.
2006-base to 2031 update (released February 2010)
Alternative series
Three alternative series (designated low, medium, and high) have been produced for each area using different fertility, mortality, and migration assumptions to illustrate a range of possible scenarios. The terms 'low', 'medium' and 'high' do not correspond to probabilities, but merely indicate the combination of assumptions. The medium projection series uses medium fertility, medium mortality and medium net migration for each area. The medium series is consistent with mid-range series 5 of the 2009-base national population projections (released in October 2009).
The low and high projection series allow users to assess the impact on population size and structure resulting from more conservative or optimistic demographic scenarios, respectively. They are independent of any series of the national population projections as they represent plausible alternative scenarios for each area rather than at the collective national level. The low projection series uses low fertility, high mortality, and low net migration for each area. The high projection series uses high fertility, low mortality, and high net migration for each area.
Users can make their own judgement as to which projection series is/are most suitable for their purposes. However, at the time of release, Statistics NZ considers the medium projection series the most suitable for assessing future population changes.
Summary table of assumptions
The projection assumptions for each territorial authority and regional council area are summarised in the following table.
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Fertility
The assumed fertility rates are based on the registered births for each area during the period 2007–09, and change consistent with the fertility variants of the national population projections.
Historical total fertility rates for subnational areas are not derived using conventional fertility methods but are merely modelled on the total number of registered live births for each area. These modelled total fertility rates should not be used as a precise measure of subnational fertility or of fertility differentials between areas. It is important to note that the objective of population projections is not to specifically measure or project the fertility of the population. For projection purposes it is more important to have a realistic yet tractable model for projecting birth numbers into the future.
Under the medium fertility assumption, the total fertility rate at the national level is assumed to increase from 1.99 births per woman in 2006 to 2.11 in 2011, decrease to 1.90 in 2026, and then remain constant. The assumed medium variant total fertility rate in 2007–11 ranges from 1.35 births per woman for Dunedin city to 3.25 for Wairoa district.
The high and low fertility variant assumptions for 2007–11 for each area are for a total fertility rate of ±0.05 births per woman from the medium assumption. By 2027–31 the high and low assumed total fertility rates are in the range of ±0.05 to ±0.29 births per woman from the medium assumption. In 2027–31 the assumed total fertility rates range from 1.28 births per woman for Dunedin city (low fertility variant) to 3.12 births per woman for Wairoa district (high fertility variant).
A sex ratio at birth of 105.5 males per 100 females is assumed, based on the historical annual average at the national level.
Mortality
The assumed mortality rates are based on the registered deaths for each area during the period 2007–09 and change consistent with the medium mortality variant of the national population projections.
Historical life expectancies at birth for subnational areas are not derived using conventional life table methods but are merely modelled on the total number of registered deaths for each area. These modelled life expectancies at birth should not be used as a precise measure of subnational mortality or of mortality differentials between areas. It is important to note that the objective of population projections is not to specifically measure or project the life expectancy of the population. For projection purposes it is more important to have a realistic yet tractable model for projecting death numbers into the future.
Under the medium mortality assumption, life expectancy at birth at the national level is assumed to increase from 78.0 years for males and 82.2 years for females in 2005–07 to 82.1 years for males and 85.3 years for females in 2031. The assumed medium variant life expectancy at birth in 2007–11 ranges from 73.8 years for males and 77.7 years for females for Kawerau district to 83.7 years for males and 87.3 years for females for Queenstown-Lakes district.
The high and low mortality variant assumptions for 2007–11 for each area are for life expectancy at birth to be about ±0.4 years for males and ±0.3 years for females from the medium assumption. By 2027–31 the high and low assumed life expectancy at birth is ±1.4 years for males and ±1.2 years for females from the medium assumption. In 2027–31 the assumed life expectancy at birth ranges from a low of 75.5 years for males and 79.1 years for females for Kawerau district to a high of 88.2 years for males and 91.0 years for females for Queenstown-Lakes district.
Migration
Migration at the subnational level has both an internal (to/from other areas of New Zealand) and an external (to/from overseas) component, although these separate components are difficult to quantify. The assumed net migration for each area is based on a consideration of observed net migration during each five-year period from 1981 to 2006, the capacity of the area for further growth (for areas with net inflow), whether historical outflows can be sustained (for areas with net outflow), the desirability of the area to new migrants, and information available from and about local authorities relating to current and future developments which may affect population change.
Under the medium migration assumption, net migration at the national level is assumed to be 71,300 in 2007–11, 54,000 in 2012–16 and 50,000 in each subsequent five-year period. Of the 73 territorial authority areas, 32 are assumed to have the same net migration level in each five-year period between 2006 and 2031. The remaining areas are assumed to have differing net migration levels during at least one of the five-year periods. Differing levels are generally assumed for areas susceptible to changes in external migration, such as university cities which have attracted large numbers of overseas students in recent years, and areas where constant net outflows are considered unsustainable.
The low and high net migration assumptions are chosen to represent plausible alternative migration scenarios for each area rather than at the collective national level. The age-sex patterns of net migration for each area are based on observed intercensal net migration patterns during 1981–2006.
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2006-base to 2031 (released December 2007)
Alternative series
Three projection series (designated low, medium and high) incorporating different fertility, mortality and migration assumptions for each area have been produced to illustrate a range of possible scenarios. The terms 'low', 'medium' and 'high' do not correspond to probabilities, but merely indicate the combination of assumptions. The medium projection series uses medium fertility, medium mortality and medium net migration for each area. The medium series is consistent with mid-range series 5 of the 2006-base national population projections (released in October 2007).
The low and high projection series allow users to assess the impact on population size and structure resulting from more conservative and optimistic demographic scenarios, respectively. They are independent of any series of the National Population Projections as they represent plausible alternative scenarios for each area rather than at the collective national level. The low projection series uses low fertility, high mortality and low net migration for each area. The high projection series uses high fertility, low mortality and high net migration for each area.
Users can make their own judgement as to which projection series is/are most suitable for their purposes. However, at the time of release, Statistics New Zealand considers the medium projection series the most suitable for assessing future population changes.
Summary table of assumptions
The projection assumptions for each territorial authority and regional council area are summarised in the following table.
 (107 KB)
Fertility
The assumed fertility rates for each area are based on the registered births for each area during 2006–07, and change that is consistent with the medium fertility variant of the 2006-base national population projections.
Historical total fertility rates for subnational areas are not derived using conventional fertility methods but are merely modelled on the total number of registered live births for each area. These modelled total fertility rates should not be used as a precise measure of subnational fertility or of fertility differentials between areas. It is important to note that the objective of population projections is not to specifically measure or project the fertility of the population. For projection purposes it is more important to have a realistic yet tractable model for projecting birth numbers into the future.
Under the medium fertility assumption, the total fertility rate at the national level is assumed to increase from 1.99 births per woman in 2006 to 2.11 in 2008, decrease to 1.90 in 2026, and then remain constant. The assumed total fertility rate in 2007–11 ranges from 1.40 births per woman for Queenstown-Lakes District to 3.10 for Wairoa District.
The high and low fertility assumptions for each area are for a total fertility rate for each five-year period ±0.1 births per woman from the medium assumption.
A sex ratio at birth of 105.5 males per 100 females is assumed, based on the historical annual average of the New Zealand population.
Mortality
The assumed mortality rates for each area are based on the registered deaths for each area during 2002–06, and change that is consistent with the medium mortality variant of the 2006-base national population projections.
Historical life expectancies at birth for subnational areas are not derived using conventional life table methods but are merely modelled on the total number of registered deaths for each area. These modelled life expectancies at birth should not be used as a precise measure of subnational mortality or of mortality differentials between areas. It is important to note that the objective of population projections is not to specifically measure or project the life expectancy of the population. For projection purposes it is more important to have a realistic yet tractable model for projecting death numbers into the future.
Under the medium mortality assumption, life expectancy at birth at the national level is assumed to increase from 78.2 years for males and 82.2 years for females in 2005–07 to 82.5 years for males and 86.2 years for females in 2031. The assumed life expectancy at birth in 2007–11 ranges from 74.3 years for males and 78.4 years for females for Wairoa District to 82.7 years for males and 86.5 years for females for Queenstown-Lakes District.
The low and high mortality assumptions for each area are for a life expectancy at birth for each five-year period ±0.5 years from the medium assumption.
Migration
Migration at the subnational level has both an internal (to/from other areas of New Zealand) and an external (to/from overseas) component, although these separate components are difficult to quantify. The assumed net migration for each area is based on a consideration of observed net migration during each five-year period from 1981 to 2006, the capacity of the area for further growth (for areas with net inflow), whether historical outflows can be sustained (for areas with net outflow), the desirability of the area to new migrants, and information available from and about local authorities relating to current and future developments which may affect population change.
Under the medium migration assumption, net migration at the national level is assumed to be 46,000 in 2007–11 and 50,000 in each subsequent five-year period. Of the 73 territorial authority areas, 59 are assumed to have the same net migration level in each five-year period between 2006 and 2031. The remaining areas are assumed to have differing net migration levels between 2006 and 2011 compared with subsequent periods. Differing levels are generally assumed for areas susceptible to changes in external migration, such as university cities which have attracted large numbers of overseas students in recent years, and areas where constant net outflows are considered unsustainable.
The low and high net migration assumptions are chosen to represent plausible alternative migration scenarios for each area rather than at the collective national level. The age-sex patterns of net migration for each area are based on observed intercensal net migration patterns during 1981–2006.
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Subnational Ethnic Population Projections
Projections (2006-base to 2021 update at five-year intervals) of the populations of 'European or Other (including New Zealander)', Māori, Asian and Pacific ethnicities, usually living in different areas of New Zealand, were released on the Statistics New Zealand website on 16 September 2010. These supersede the subnational ethnic population projections, 2006-base to 2021, released on the Statistics New Zealand website on 30 September 2008.
The projections have been released for selected geographic areas, broad ethnic groups and a projection period of 15 years because of the small size of many subnational ethnic populations and because of the uncertain nature of ethnic population projections as discussed in Nature of Projections (above).
- 'European or Other' population projections are available for all 16 regional council areas (regions) and 72 of the 73 territorial authority areas (cities and districts).
- Māori population projections are available for 16 regions and 56 territorial authority areas.
- Asian population projections are available for 10 regions and 17 territorial authority areas.
- Pacific population projections are available for 9 regions and 18 territorial authority areas.
However, ethnic projections for regions and territorial authority areas not released are available as customised projections provided the client agrees to the projection assumptions. For more information and quotes, email demography@stats.govt.nz or telephone 0508 525 525 toll free.
Ethnic concept
The ethnic concept used in these projections is the ethnic group or groups that people identify with or feel they belong to. Ethnicity is self-perceived and people can belong to more than one ethnic group. For example, people may identify with the Māori ethnicity even though they are not descended from a Māori ancestor. Conversely, people may choose to not identify with the Māori ethnicity even though they are descended from a Māori ancestor. Ethnicity is not the same as birthplace.
People who identify with more than one ethnicity are included in each ethnic population. Therefore, the ethnic population projections are not mutually exclusive.
For more information about ethnicity, refer to the Review of the Measurement of Ethnicity which includes information about the Statistical Standard for Ethnicity 2005.
European or Other
Projections have been derived for the 'European or Other (including New Zealander)' ethnic group. Projections are not available for the European ethnic group, or for the Other (including New Zealander) ethnic group. This reflects that sufficient demographic data is available to enable projection assumptions to be derived for the combined ethnic grouping, but not for the separate ethnic groups. This approach is consistent with Guidelines for Using Ethnicity Data: 2006 Census.
Base population
These projections have as a base the estimated resident population of each ethnic group, of each area, at 30 June 2006. These populations were based on the census usually resident population count at 7 March 2006 with adjustments for:
- non-response to the census ethnicity question
- net census undercount
- residents temporarily overseas on census night
- births, deaths and net migration between census night (7 March 2006) and 30 June 2006
- reconciliation with demographic estimates at ages 0–4 years.
For more information about the base population, refer to Population Estimates.
2006-base to 2021 (released September 2010)
Alternative series
Three alternative series (designated low, medium and high) have been produced for each ethnic group and each area using different fertility, mortality, migration and inter-ethnic mobility assumptions. The terms 'low', 'medium' and 'high' do not correspond to probabilities, but merely indicate the combination of assumptions. The medium projection series uses medium fertility, medium mortality, medium migration and medium inter-ethnic mobility for each ethnic group and each area. At the time of release, the medium projection series is considered the most suitable for assessing future population change and is consistent with the medium series of the updated 2006-base subnational population projections released on 24 February 2010, and series 6 of the respective updated 2006-base national ethnic population projections released on 22 April 2010. In turn, these series are consistent with series 5 of the 2009-base national population projections released on 27 October 2009.
The low projection series assumes low fertility, high mortality, low migration and high inter-ethnic mobility for each ethnic group and each area. The high projection series assumes high fertility, low mortality, high migration and low inter-ethnic mobility for each ethnic group and each area. The low and high series are independent of other national or subnational projections as they represent plausible alternative scenarios for each ethnic group and each area only, rather than for any collective ethnic or geographic level. For example, the high series of the subnational Māori population projections cannot be directly compared with any series of the subnational population projections (total population) because the assumptions are not necessarily compatible.
Summary table of assumptions
The projection assumptions for each ethnic group and territorial authority area and regional council area are summarised in the following table.
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Fertility
The assumed fertility and paternity rates for each area are based on the registered births for each area during the period 2006–10, and change that is consistent with the fertility and paternity variants of the respective national ethnic population projections.
Historical total fertility rates for subnational areas are not derived using conventional fertility methods but are merely modelled on the total number of registered live births for each area. These modelled total fertility rates should not be used as a precise measure of subnational fertility or of fertility differentials between areas or between ethnic groups. It is important to note that the objective of population projections is not to specifically measure or project the fertility of the population. For projection purposes it is more important to have a realistic yet tractable model for projecting birth numbers into the future.
Under the medium fertility assumption:
- European or Other: The total fertility rate at the national level is assumed to drop from about 2.0 births per woman in 2007–11 to about 1.9 in 2017–21. Of those areas where projections have been released, the assumed total fertility rate in 2007–11 ranges from 2.9 births per woman for Wairoa and South Wairarapa districts to 1.4 for Wellington and Dunedin cities.
- Māori: The total fertility rate at the national level is assumed to drop from about 2.8 births per woman in 2007–11 to 2.5 in 2017–21. Of those areas where projections have been released, the assumed total fertility rate in 2007–11 ranges from 3.8 births per woman for Ruapehu District to 1.5 for Wellington City.
- Asian: The total fertility rate at the national level is assumed to remain about 1.5 births per woman during 2007–21. Of those areas where projections have been released, the assumed total fertility rate in 2007–11 ranges from 2.2 births per woman for Tauranga City to 0.8 for Dunedin City.
- Pacific: The total fertility rate at the national level is assumed to drop from about 3.0 births per woman in 2007–11 to 2.7 in 2017–21. Of those areas where projections have been released, the assumed total fertility rate in 2007–11 ranges from 3.7 births per woman for Tauranga City to 1.7 for Dunedin City.
Under the medium paternity assumption:
- European or Other: The total paternity rate at the national level is assumed to remain about 0.2 births per man during 2007–21. Of those areas where projections have been released, the assumed total paternity rate in 2007–11 ranges from 0.8 births per man for Kawerau District to 0.1 for Carterton and Waitaki districts.
- Māori: The total paternity rate at the national level is assumed to drop from about 1.1 births per man during 2007–11 to about 1.0 during 2017–21. Of those areas where projections have been released, the assumed total paternity rate in 2007–11 ranges from 1.9 births per man for Waimakariri District to 0.3 for Opotiki District.
- Asian: The total paternity rate at the national level is assumed to remain about 0.2 births per man during 2007–21. Of those areas where projections have been released, the assumed total paternity rate in 2007–11 ranges from 1.0 births per man for Porirua City to 0.1 for North Shore and Auckland cities.
- Pacific: The total paternity rate at the national level is assumed to drop from about 1.1 births per man during 2007–11 to about 1.0 during 2017–21. Of those areas where projections have been released, the assumed total paternity rate in 2007–11 ranges from 2.7 births per man for Tauranga City to 0.6 for Auckland City.
The high and low fertility assumptions for each area are for a total fertility rate:
- European or Other: Approximately ±0.10 births per woman from the medium assumption during 2007–11, increasing to ±0.21 births per woman from the medium assumption during 2017–21.
- Māori: Approximately ±0.10 births per woman from the medium assumption during 2007–11, increasing to ±0.25 births per woman from the medium assumption during 2017–21.
- Asian: Approximately ±0.10 births per woman from the medium assumption during 2007–11, increasing to ±0.19 births per woman from the medium assumption during 2017–21.
- Pacific: Approximately ±0.10 births per woman from the medium assumption during 2007–11, increasing to ±0.23 births per woman from the medium assumption during 2017–21.
The high and low paternity assumptions for each area are for a total paternity rate:
- European or Other: Approximately ±0.04 births per man from the medium assumption during 2007–11, increasing to ±0.06 births per man from the medium assumption during 2017–21.
- Māori: Approximately ±0.10 births per man from the medium assumption during 2007–11, increasing to ±0.15 births per man from the medium assumption during 2017–21.
- Asian: Approximately ±0.04 births per man from the medium assumption during 2007–11, increasing to ±0.06 births per man from the medium assumption during 2017–21.
- Pacific: Approximately ±0.10 births per man from the medium assumption during 2007–11, increasing to ±0.22 births per man from the medium assumption during 2017–21.
A sex ratio at birth of 105.5 males per 100 females is assumed, based on the historical annual average of the New Zealand population.
For each ethnic group, projected births are reduced to allow for births to parent(s) of that ethnic group that are not registered as children of that ethnic group. The low, medium and high assumptions are, respectively:
- European or Other: 1.6, 2.1 and 2.6 percent of births to European or Other parent(s) are non-European and non-Other children.
- Māori: 3.4, 3.9 and 4.4 percent of births to Māori parent(s) are non-Māori children.
- Asian: 2.9, 3.4 and 3.9 percent of births to Asian parent(s) are non-Asian children.
- Pacific: 2.6, 3.1 and 3.6 percent of births to Pacific parent(s) are non-Pacific children.
Mortality
The assumed mortality rates for each area are based on the registered deaths for each area during the period 2006–10, and change that is consistent with the mortality variants of the respective national ethnic population projections.
Historical life expectancies at birth for subnational areas are not derived using conventional life table methods but are merely modelled on the total number of registered deaths for each area. These modelled life expectancies at birth should not be used as a precise measure of subnational mortality or of mortality differentials between areas or between ethnic groups. It is important to note that the objective of population projections is not to specifically measure or project the life expectancy of the population. For projection purposes it is more important to have a realistic yet tractable model for projecting death numbers into the future.
Under the medium mortality assumption:
- European or Other: Life expectancy at birth at the national level is assumed to increase from 79.5 years for males and 83.3 years for females in 2007–11 to 81.1 years for males and 84.5 years for females in 2017–21. Of those areas where projections have been released, the assumed life expectancy at birth in 2007–11 ranges from 77.1 years for males and 81.2 years for females for Kawerau District to 84.4 years for males and 87.9 years for females for Mackenzie District.
- Māori: Life expectancy at birth at the national level is assumed to increase from 71.5 years for males and 76.1 years for females in 2007–11 to 73.8 years for males and 77.9 years for females in 2017–21. Of those areas where projections have been released, the assumed life expectancy at birth in 2007–11 ranges from 66.8 years for males and 71.8 years for females in South Waikato District to 81.8 years for males and 85.7 years for females in Thames-Coromandel District.
- Asian: Life expectancy at birth at the national level is assumed to increase from 84.0 years for males and 87.5 years for females in 2007–11 to 85.5 years for males and 88.7 years for females in 2017–21. Of those areas where projections have been released, the assumed life expectancy at birth in 2007–11 ranges from 78.2 years for males and 82.1 years for females in Hastings District to 87.5 years for males and 90.8 years for females in North Shore City.
- Pacific: Life expectancy at birth at the national level is assumed to increase from 73.8 years for males and 77.8 years for females in 2007–11 to 75.6 years for males and 79.3 years for females in 2017–21. Of those areas where projections have been released, the assumed life expectancy at birth in 2007–11 ranges from 70.5 years for males and 74.8 years for females in Rotorua District to 84.0 years for males and 87.3 years for females in Palmerston North City.
The low and high mortality assumptions for each ethnic group for each area are for a life expectancy at birth approximately ±0.8 years for males and ±0.7 years for females from the medium assumption during 2007–11, increasing to ±1.6 years for males and ±1.3 years for females from the medium assumption during 2017–21.
Migration
Migration at the subnational level has both an internal (to/from other areas of New Zealand) and an external (to/from overseas) component, although these separate components are difficult to quantify. Ethnicity is not collected in international travel and migration data, but the assumed migration is based on an assessment of recent and expected trends of arrivals and departures of New Zealand citizens and non-New Zealand citizens by country of birth.
The assumed future net migration for each area is also based on a consideration of observed net migration during 1997–2006, the capacity of the area for further growth (for areas with net inflow), whether historical outflows can be sustained (for areas with net outflow), the desirability of the area to new migrants, and information available from and about local authorities relating to current and future developments which may affect population change.
Migration assumptions at the subnational level reflect the assumptions at the national level. Under the medium migration assumption:
- European or Other: net migration at the national level is assumed to be zero in 2007–11, -11,000 in 2012–16 and -15,000 in 2017–21. Of the 72 territorial authority areas for which European or Other population projections have been released, 21 areas assume a net migration gain in all three five-year periods; 35 areas assume a net migration loss in all three five-year periods; and 3 areas assume zero net migration in all three five-year periods. Net migration for 6 territorial authority areas is assumed to increase between 2007–11 and 2012–16 and then stay constant. Net migration for 43 territorial authority areas is assumed to decrease between 2007–11 and 2012–16 and then stay constant. Net migration for 18 territorial authority areas is assumed to stay constant throughout the projection period.
- Māori: net migration at the national level is assumed to be -18,000 in 2007–11 and -15,000 in 2012–16 and 2017–21. Of the 56 territorial authority areas for which Māori population projections have been released, 5 areas assume a net migration gain in all three five-year periods; 42 areas assume a net migration loss in all three five-year periods; and 3 areas assume zero net migration in all three five-year periods. Another 3 areas assume a net migration loss in 2007–11 and zero net migration in 2012–16 and 2017–21. Net migration for 20 territorial authority areas is assumed to increase between 2007–11 and 2012–16 and then stay constant. Net migration for 7 territorial authority areas is assumed to decrease between 2007–11 and 2012–16 and then stay constant. Net migration for 29 territorial authority areas is assumed to stay constant throughout the projection period.
- Asian: net migration at the national level is assumed to be 68,000 in 2007–11 and 60,000 in 2012–16 and 2017–21. Of the 17 territorial authority areas for which Asian population projections have been released, all areas assume a net migration gain in all three five-year periods. Net migration for 10 territorial authority areas is assumed to decrease between 2007–11 and 2012–16 and then stay constant. Net migration for 7 territorial authority areas is assumed to stay constant throughout the projection period.
- Pacific: net migration at the national level is assumed to be 3,000 in 2007–11 and 2,500 in 2012–16 and 2017–21. Of the 18 territorial authority areas for which Pacific population projections have been released, 10 areas assume a net migration gain in all three five-year periods; 7 areas assume a net migration loss in all three five-year periods; and 1 area assumes zero net migration in all three five-year periods. Net migration for 1 territorial authority area is assumed to decrease between 2007–11 and 2012–16 and then stay constant. Net migration for 17 territorial authority areas is assumed to stay constant throughout the projection period.
The low and high net migration assumptions are chosen to represent plausible alternative migration scenarios for each area rather than at the collective national level.
The age-sex patterns of net migration for each area are based on observed intercensal net migration patterns during 1997–2006.
Inter-ethnic mobility
There are three alternative inter-ethnic mobility variants which assume net change to each ethnic population due to people changing their ethnic identification over time. The age pattern of inter-ethnic mobility is applied to each sex and assumes the highest net mobility at ages 12–26 years. The low, medium and high assumptions on an annual rate (in 2007) are, respectively:
- European or Other: 0.2, zero and -0.2 percent.
- Māori: zero, -0.3 and -0.6 percent.
- Asian: zero, -0.2 and -0.4 percent.
- Pacific: zero, -0.2 and -0.4 percent.
Regional projections
Ethnic population projections for regional council areas (regions) have not been produced directly but by combining projections for territorial authority areas (TAs). Of the 73 TAs, 8 TAs are split over two or more regions, while the remaining 65 TAs are completely within one region.
Where TAs are split, the TA projections for each ethnicity are split according to the base population (estimated resident population of each ethnic group of each area at 30 June 2006). For example, Franklin District is split between Auckland and Waikato regions. In 2006, 67 percent of the estimated Māori population in Franklin District was in Auckland Region, and the remaining 33 percent lived in Waikato Region. This split factor (67:33) has been applied to all projected Māori age-sex population cells, births, deaths and age-sex migration cells of Franklin District.
Those variables which cannot be obtained by summation, such as median age and total fertility rate, are recalculated for regions after combining the TA projections.
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2006-base to 2021 (released September 2008)
Alternative series
Three alternative series (designated low, medium and high) have been produced for each ethnic group and each area using different fertility, mortality, migration and inter-ethnic mobility assumptions. The terms 'low', 'medium' and 'high' do not correspond to probabilities, but merely indicate the combination of assumptions. The medium projection series uses medium fertility, medium mortality, medium migration and medium inter-ethnic mobility for each ethnic group and each area. At the time of release, the medium projection series is considered the most suitable for assessing future population change and is consistent with the medium series of the 2006-base subnational population projections released on 3 December 2007, and series 6 of the respective 2006-base national ethnic population projections released on 2 April 2008. In turn, these series are consistent with series 5 of the 2006-base national population projections released on 24 October 2007.
The low projection series assumes low fertility, high mortality, low migration and high inter-ethnic mobility for each ethnic group and each area. The high projection series assumes high fertility, low mortality, high migration and low inter-ethnic mobility for each ethnic group and each area. The low and high series are independent of other national or subnational projections as they represent plausible alternative scenarios for each ethnic group and each area only, rather than for any collective ethnic or geographic level. For example, the high series of the subnational Māori population projections cannot be directly compared with any series of the subnational population projections (total population) because the assumptions are not necessarily compatible.
Summary table of assumptions
The projection assumptions for each ethnic group and territorial authority area and regional council area are summarised in the following table.
 (165 KB)
Fertility
The assumed fertility and paternity rates for each area are based on the registered births for each area during the period 2006–08, and change that is consistent with the fertility and paternity variants of the respective national ethnic population projections.
Historical total fertility rates for subnational areas are not derived using conventional fertility methods but are merely modelled on the total number of registered live births for each area. These modelled total fertility rates should not be used as a precise measure of subnational fertility or of fertility differentials between areas or between ethnic groups. It is important to note that the objective of population projections is not to specifically measure or project the fertility of the population. For projection purposes it is more important to have a realistic yet tractable model for projecting birth numbers into the future.
Under the medium fertility assumption:
- European or Other: The total fertility rate at the national level is assumed to drop from about 2.1 births per woman in 2007–11 to about 1.8 in 2017–21. The assumed total fertility rate in 2007–11 ranges from 3.2 births per woman for Wairoa District to 1.4 for Dunedin City.
- Māori: The total fertility rate at the national level is assumed to drop from about 3.0 births per woman in 2007–11 to 2.6 in 2017–21. Of those areas where projections have been released, the assumed total fertility rate in 2007–11 ranges from 4.1 births per woman for Ruapehu District to 1.5 for Wellington City.
- Asian: The total fertility rate at the national level is assumed to remain about 1.6 births per woman during 2007–21. Of those areas where projections have been released, the assumed total fertility rate in 2007–11 ranges from 2.4 births per woman for Tauranga City to 1.1 for Dunedin City.
- Pacific: The total fertility rate at the national level is assumed to drop from about 3.1 births per woman in 2007–11 to 2.7 in 2017–2021. Of those areas where projections have been released, the assumed total fertility rate in 2007–11 ranges from 3.8 births per woman for Tauranga City to 1.7 for Dunedin City.
Under the medium paternity assumption:
- European or Other: The total paternity rate at the national level is assumed to drop from about 0.2 births per man during 2007–11 to about 0.1 during 2017–21. The assumed total paternity rate in 2007–11 ranges from 0.7 births per man for Kawerau District to 0.0 for Carterton District.
- Māori: The total paternity rate at the national level is assumed to drop from about 1.1 births per man during 2007–11 to about 1.0 during 2017–21. Of those areas where projections have been released, the assumed total paternity rate in 2007–11 ranges from 2.1 births per man for Waimakariri District to 0.3 for Opotiki District.
- Asian: The total paternity rate at the national level is assumed to remain about 0.2 births per man during 2007–21. Of those areas where projections have been released, the assumed total paternity rate in 2007–11 ranges from 0.9 births per man for Porirua City to 0.1 for North Shore and Auckland cities.
- Pacific: The total paternity rate at the national level is assumed to drop from about 1.2 births per man during 2007–11 to about 1.1 during 2017–21. Of those areas where projections have been released, the assumed total paternity rate in 2007–11 ranges from 2.8 births per man for Tauranga City to 0.7 for Auckland City.
The high and low fertility assumptions for each area are for a total fertility rate:
- European or Other: Approximately ±0.10 births per woman from the medium assumption during 2007–11, increasing to ±0.19 births per woman from the medium assumption during 2017–21.
- Māori: Approximately ±0.10 births per woman from the medium assumption during 2007–11, increasing to ±0.25 births per woman from the medium assumption during 2017–21.
- Asian: Approximately ±0.10 births per woman from the medium assumption during 2007–11, increasing to ±0.18 births per woman from the medium assumption during 2017–21.
- Pacific: Approximately ±0.10 births per woman from the medium assumption during 2007–11, increasing to ±0.24 births per woman from the medium assumption during 2017–21.
The high and low paternity assumptions for each area are for a total paternity rate:
- European or Other: Approximately ±0.04 births per man from the medium assumption during 2007–11, increasing to ±0.05 births per man from the medium assumption during 2017–21.
- Māori: Approximately ±0.10 births per man from the medium assumption during 2007–11, increasing to ±0.16 births per man from the medium assumption during 2017–21.
- Asian: Approximately ±0.04 births per man from the medium assumption during 2007–11, increasing to ±0.06 births per man from the medium assumption during 2017–21.
- Pacific: Approximately ±0.10 births per man from the medium assumption during 2007–11, increasing to ±0.16 births per man from the medium assumption during 2017–21.
A sex ratio at birth of 105.5 males per 100 females is assumed, based on the historical annual average of the New Zealand population.
For each ethnic group, projected births are reduced to allow for births to parent(s) of that ethnic group that are not registered as children of that ethnic group. The low, medium and high assumptions are, respectively:
- European or Other: 1.7, 2.2 and 2.7 percent of births to European or Other parent(s) are non-European and non-Other children.
- Māori: 3.5, 4.0 and 4.5 percent of births to Māori parent(s) are non-Māori children.
- Asian: 3.1, 3.6 and 4.1 percent of births to Asian parent(s) are non-Asian children.
- Pacific: 2.8, 3.3 and 3.8 percent of births to Pacific parent(s) are non-Pacific children.
Mortality
The assumed mortality rates for each area are based on the registered deaths for each area during the period 2006–08, and change that is consistent with the mortality variants of the respective national ethnic population projections.
Historical life expectancies at birth for subnational areas are not derived using conventional life table methods but are merely modelled on the total number of registered deaths for each area. These modelled life expectancies at birth should not be used as a precise measure of subnational mortality or of mortality differentials between areas or between ethnic groups. It is important to note that the objective of population projections is not to specifically measure or project the life expectancy of the population. For projection purposes it is more important to have a realistic yet tractable model for projecting death numbers into the future.
Under the medium mortality assumption:
- European or Other: Life expectancy at birth at the national level is assumed to increase from 79.8 years for males and 83.5 years for females in 2007–11 to 81.6 years for males and 85.2 years for females in 2017–21. The assumed life expectancy at birth in 2007–11 ranges from 76.8 years for males and 80.8 years for females for Ruapehu District to 86.3 years for males and 89.6 years for females for Mackenzie District.
- Māori: Life expectancy at birth at the national level is assumed to increase from 71.2 years for males and 75.9 years for females in 2007–11 to 74.5 years for males and 78.8 years for females in 2017–21. Of those areas where projections have been released, the assumed life expectancy at birth in 2007–11 ranges from 65.8 years for males and 70.9 years for females in South Waikato District to 81.6 years for males and 85.6 years for females in Thames-Coromandel District.
- Asian: Life expectancy at birth at the national level is assumed to increase from 84.2 years for males and 87.4 years for females in 2007–11 to 85.0 years for males and 88.3 years for females in 2017–21. Of those areas where projections have been released, the assumed life expectancy at birth in 2007–11 ranges from 78.5 years for males and 82.1 years for females in Hastings District to 89.0 years for males and 91.8 years for females in North Shore City.
- Pacific: Life expectancy at birth at the national level is assumed to increase from 73.5 years for males and 77.8 years for females in 2007–11 to 76.6 years for males and 80.6 years for females in 2017–21. Of those areas where projections have been released, the assumed life expectancy at birth in 2007–11 ranges from 68.4 years for males and 73.1 years for females in Rodney District to 79.3 years for males and 83.2 years for females in Papakura District.
The low and high mortality assumptions for each area are for a life expectancy at birth:
- European or Other: Approximately ±0.8 years for males and ±0.7 years for females from the medium assumption during 2007–11, increasing to ±1.5 years for males and ±1.3 years for females from the medium assumption during 2017–21.
- Māori: Approximately ±0.8 years for males and ±0.7 years for females from the medium assumption during 2007–11, increasing to ±1.5 years for males and ±1.3 years for females from the medium assumption during 2017–21.
- Asian: Approximately ±0.8 years for males and ±0.7 years for females from the medium assumption during 2007–11, increasing to ±1.5 years for males and ±1.3 years for females from the medium assumption during 2017–21.
- Pacific: Approximately ±0.8 years for males and ±0.7 years for females from the medium assumption during 2007–11, increasing to ±1.5 years for males and ±1.3 years for females from the medium assumption during 2017–21.
Migration
Migration at the subnational level has both an internal (to/from other areas of New Zealand) and an external (to/from overseas) component, although these separate components are difficult to quantify. Ethnicity is not collected in international travel and migration data, but the assumed migration is based on an assessment of recent and expected trends of arrivals and departures of New Zealand citizens and non-New Zealand citizens by country of birth.
The assumed future net migration for each area is also based on a consideration of observed net migration during 1997–2006, the capacity of the area for further growth (for areas with net inflow), whether historical outflows can be sustained (for areas with net outflow), the desirability of the area to new migrants, and information available from and about local authorities relating to current and future developments which may affect population change.
Migration assumptions at the subnational level echo the assumptions at the national level. Under the medium migration assumption:
- European or Other: net migration at the national level is assumed to be -18,000 in 2007–11 and -15,000 in 2012–16 and 2017–21. Of the 72 territorial authority areas for which European or Other population projections have been released, 21 areas assume a net migration gain, 48 areas assume a net migration loss, and 3 areas assume zero net migration in all three five-year periods. Net migration for 13 territorial authority areas is assumed to increase between 2007–11 and 2012–16 and then stay constant. Net migration for 20 territorial authority areas is assumed to decrease between 2007–11 and 2012–16 and then stay constant. Net migration for 39 territorial authority areas is assumed to stay constant throughout the projection period.
- Māori: net migration at the national level is assumed to be -19,500 in 2007–11 and -15,000 in 2012–16 and 2017–21. Of the 56 territorial authority areas for which Māori population projections have been released, 4 areas assume a net migration gain, 43 areas assume a net migration loss, and 5 areas assume zero net migration in all three five-year periods. Another 4 areas assume a net migration loss in 2007–11 and zero net migration in 2012–16 and 2017–21. Net migration for 26 territorial authority areas is assumed to increase between 2007–11 and 2012–16 and then stay constant. Net migration for 30 territorial authority areas is assumed to stay constant throughout the projection period.
- Asian: net migration at the national level is assumed to be 63,000 in 2007–11 and 60,000 in 2012–16 and 2017–21. Of the 17 territorial authority areas for which Asian population projections have been released, all areas assume a net migration gain in all three five-year periods. Net migration for 4 territorial authority areas is assumed to decrease between 2007–11 and 2012–16 and then stay constant. Net migration for 13 territorial authority areas is assumed to stay constant throughout the projection period.
- Pacific: net migration at the national level is assumed to be 3,000 in 2007–11 and 2,500 in 2012–16 and 2017–21. Of the 18 territorial authority areas for which Pacific population projections have been released, 10 areas assume a net migration gain, 7 areas assume a net migration loss, and 1 area assumes zero net migration in all three five-year periods. Net migration for 1 territorial authority area is assumed to decrease between 2007–11 and 2012–16 and then stay constant. Net migration for 17 territorial authority areas is assumed to stay constant throughout the projection period.
The low and high net migration assumptions are chosen to represent plausible alternative migration scenarios for each area rather than at the collective national level.
The age-sex patterns of net migration for each area are based on observed intercensal net migration patterns during 1997–2006.
Inter-ethnic mobility
There are three alternative inter-ethnic mobility variants which assume net change to each ethnic population due to people changing their ethnic identification over time. The age pattern of inter-ethnic mobility is applied to each sex and assumes the highest net mobility at ages 12–26 years. The low, medium and high assumptions on an annual rate (in 2007) are, respectively:
- European or Other: 0.2, zero and -0.2 percent.
- Māori: zero, -0.3 and -0.6 percent.
- Asian: zero, -0.2 and -0.4 percent.
- Pacific: zero, -0.2 and -0.4 percent.
Regional projections
Ethnic population projections for regional council areas (regions) have not been produced directly but by combining projections for territorial authority areas (TAs). Of the 73 TAs, 8 TAs are split over two or more regions, while the remaining 65 TAs are completely within one region.
Where TAs are split, the TA projections for each ethnicity are split according to the base population (estimated resident population of each ethnic group of each area at 30 June 2006). For example, Franklin District is split between Auckland and Waikato regions. In 2006, 67 percent of the estimated Māori population in Franklin District was in Auckland Region, and the remaining 33 percent lived in Waikato Region. This split factor (67:33) has been applied to all projected Māori age-sex population cells, births, deaths and age-sex migration cells of Franklin District.
Those variables which cannot be obtained by summation, such as median age and total fertility rate, are recalculated for regions after combining the TA projections.
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Subnational Family and Household Projections
Projections Projections (2006-base to 2031 update at five-year intervals) of families and households usually living in the 16 regional council areas and 73 territorial authority areas (cities and districts) of New Zealand were released via Hot Off the Press (ISSN 1179-321x) on 13 December 2010. These supersede the Subnational Family and Household Projections, 2006(base)–2031, released via Hot Off the Press (ISSN 1179-321X) on 17 July 2009. The family and household projections are derived from projections of the population, by multiplying the projected population by the assumed living arrangement type rates for each age-sex group. The projections of population by living arrangement type are subsequently aggregated to give projections of families (by broad family type) and households (by broad household type).
Family and household concepts
These projections are based on the definitions of family and household used in the 2006 Census of Population and Dwellings. A family is defined as a couple, with or without children, or one parent with children, usually living together in a household. A household is defined as one person usually living alone, or two or more people usually living together and sharing facilities (for example, eating facilities, cooking facilities, bathroom and toilet facilities, a living area) in a private dwelling. No information is available from the census on families and households extending beyond a single dwelling, or on families defined using different concepts (for example, whanau), and minimal information is available on families in non-private dwellings.
In these family and household projections, all people are allocated to one of 11 living arrangement types. The living arrangement type refers to the usual family and household role of a person based on a combination of individual, family, household and dwelling information from the census. The projections are based on allocating people to one role from several broad roles they may have within each social structure. These roles vary by age and sex, and are assumed to change over time with changes in social patterns.
The projections do not give a complete picture of the complexity of family and household structures, because people can and do have more than one living arrangement type role in any one entity, and families and households are not necessarily synonymous. Although people can have more than one residence, their living arrangement type role is generally based on the family and household structure of where they usually live, as self-identified by them in the census. Because households are defined as discrete units, the fluidity of living arrangements where people are associated with more than one household for study, work or shared-care purposes is not addressed.
Opposite-sex and same-sex couples are not projected separately, but are included in projections of 'couple without children' and 'two-parent' families.
It is also important to note that the definitions of parents and children are social, not biological. For example, parents include people usually living with at least one of their natural, step-, adopted or foster children (who is not usually living with a partner or child of their own). Similarly, a child is a person of any age usually living with one or two natural, step-, or adopted parents, or person in a parent role (but not usually living with a partner or child of their own). No information is available on the strength of identified parent-child relationships in terms of emotional and/or financial support.
Base population
These projections have as a base the estimated resident population of each area at 30 June 2006. This population was based on the census usually resident population count of each area at 7 March 2006 with adjustments for:
1. net census undercount
2. residents temporarily overseas on census night
3. births, deaths and net migration between census night (7 March 2006) and 30 June 2006
4. reconciliation with demographic estimates at ages 0–4 years.
For more information about the base population, refer to Population Estimates.
The estimated numbers of families and households are derived indirectly from the estimated resident population and the estimated living arrangement type rates for each age-sex group. The estimated number of families and households are equivalent to the census family count and census household count, respectively, at 7 March 2006, with adjustments for:
1. net census undercount
2. families and households temporarily overseas on census night
3. change between census night (7 March 2006) and 30 June 2006
4. families and households temporarily away from their usual residence, but in New Zealand, on census night.
Method
A special propensity method has been used to derive the family and household projections. By this method, living arrangement type rates (or propensities) are applied to population projections to give projections of the population in different living arrangement types. These projections are subsequently aggregated to give projections of families (by broad family type) and households (by broad household type).
The number of couple without children families = (male partners in couple without children families + female partners in couple without children families) ÷ 2.
The number of two-parent families = (male partners/parents in two-parent families + female partners/parents in two-parent families) ÷ 2.
The number of one-parent families = male parents in one-parent families + female parents in one-parent families.
The number of family households = number of families ÷ average number of families per family household.
The number of one-person households = number of people in one-person households.
The number of other multiperson households = number of people in other multiperson households ÷ average number of people per other multiperson household.
2006-base to 2031 update (released December 2010)
Alternative series
Three alternative subnational family and household projection series (designated low, medium and high) have been produced for each area using different population projection series (with different fertility, mortality and migration assumptions). One set of living arrangement type assumptions has been used for all three series. The terms 'low', 'medium' and 'high' do not correspond to probabilities, but merely indicate the combination of assumptions.
The medium projection series uses the medium series of the Subnational Population Projections: 2006(base) update (released on 24 February 2010), which assumes medium fertility, medium mortality and medium net migration for each area. The medium subnational family and household projection series is consistent with series 5B of the National Family and Household Projections: 2006(base)–2031 update (released 19 July 2010) and series 5 of the National Population Projections 2009(base)–2061 (released on 27 October 2009).
The low projection series uses low fertility, high mortality and low net migration for each area. The high projection series uses high fertility, low mortality and high net migration for each area. The low and high projection series allow users to assess the impact on the number and type of families and households resulting from different population scenarios. The low and high series have been formulated to give plausible alternative scenarios for each area rather than at any collective geographical level. Neither series is consistent with any of the alternative series of the National Family and Household Projections 2006(base) update.
Users can make there own judgement as to which projection series is/are most suitable for their purposes. However, at the time of release, Statistics NZ considers the medium projection series the most suitable for assessing future family and household changes.
Fertility
The assumed fertility rates are based on the registered births for each area during the period 2007–09 and change consistent with the fertility variants of the national population projections.
Historical total fertility rates for subnational areas are not derived using conventional fertility methods but are merely modelled on the total number of registered live births for each area. These modelled total fertility rates should not be used as a precise measure of subnational fertility or of fertility differentials between areas. It is important to note that the objective of population projections is not to specifically measure or project the fertility of the population. For projection purposes it is more important to have a realistic yet tractable model for projecting birth numbers into the future.
Under the medium fertility assumption, the total fertility rate at the national level is assumed to increase from 1.99 births per woman in 2006 to 2.11 in 2011, decrease to 1.90 in 2026, and then remain constant. The assumed medium variant total fertility rate in 2007–11 ranges from 1.35 births per woman for Dunedin city to 3.25 for Wairoa district.
The high and low fertility variant assumptions for 2007–11 for each area are for a total fertility rate of ±0.05 births per woman from the medium assumption. By 2027–31 the high and low assumed total fertility rates are in the range of ±0.05 to ±0.29 births per woman from the medium assumption. In 2027–31 the assumed total fertility rates range from 1.28 births per woman for Dunedin city (low fertility variant) to 3.12 births per woman for Wairoa district (high fertility variant).
A sex ratio at birth of 105.5 males per 100 females is assumed, based on the historical annual average at the national level.
Mortality
The assumed mortality rates are based on the registered deaths for each area during the period 2007–09 and change consistent with the mortality variant of the national population projections.
Historical life expectancies at birth for subnational areas are not derived using conventional life table methods but are merely modelled on the total number of registered deaths for each area. These modelled life expectancies at birth should not be used as a precise measure of subnational mortality or of mortality differentials between areas. It is important to note that the objective of population projections is not to specifically measure or project the life expectancy of the population. For projection purposes it is more important to have a realistic yet tractable model for projecting death numbers into the future.
Under the medium mortality assumption, life expectancy at birth at the national level is assumed to increase from 78.0 years for males and 82.2 years for females in 2005–07 to 82.1 years for males and 85.3 years for females in 2031. The assumed medium variant life expectancy at birth in 2007–11 ranges from 73.8 years for males and 77.7 years for females for Kawerau district to 83.7 years for males and 87.3 years for females for Queenstown-Lakes district.
The high and low mortality variant assumptions for 2007–11 for each area are for life expectancy at birth to be about ±0.4 years for males and ±0.3 years for females from the medium assumption. By 2027–31 the high and low assumed life expectancy at birth is ±1.4 years for males and ±1.2 years for females from the medium assumption. In 2027–31 the assumed life expectancy at birth ranges from a low of 75.5 years for males and 79.1 years for females for Kawerau district to a high of 88.2 years for males and 91.0 years for females for Queenstown-Lakes district.
Migration
Migration at the subnational level has both an internal (to/from other areas of New Zealand) and an external (to/from overseas) component, although these separate components are difficult to quantify. The assumed net migration for each area is based on a consideration of observed net migration during each five-year period from 1981 to 2006, the capacity of the area for further growth (for areas with net inflow), whether historical outflows can be sustained (for areas with net outflow), the desirability of the area to new migrants, and information available from and about local authorities relating to current and future developments which may affect population change.
Under the medium migration assumption, net migration at the national level is assumed to be 71,300 in 2007–11, 54,000 in 2012–16 and 50,000 in each subsequent five-year period. Of the 73 territorial authority areas, 32 are assumed to have the same net migration level in each five-year period between 2006 and 2031. The remaining areas are assumed to have differing net migration levels during at least one of the five-year periods. Differing levels are generally assumed for areas susceptible to changes in external migration, such as university cities which have attracted large numbers of overseas students in recent years, and areas where constant net outflows are considered unsustainable.
The low and high net migration assumptions are chosen to represent plausible alternative migration scenarios for each area rather than at the collective national level. The age-sex patterns of net migration for each area are based on observed intercensal net migration patterns during 1981–2006.
Living arrangement type rates (LATRs)
One LATR variant is used for all three subnational family and household projection series. This assumes that LATRs will change linearly between 2006 and 2031, based on an assessment of observed trends between 1986 and 2006, and likely future trends, by sex and five-year age group. The LATRs are constrained so that the medium series of the Subnational Family and Household Projections 2006(base) update sums to series 5B of the National Family and Household Projections: 2006(base) update (released 19 July 2010) for population (by living arrangement type, five-year age group and sex), for families (by family type) and for households (by household type). While assumed trends in living arrangement type rates do vary by area, they are generally consistent with assumed trends at the national level.
Additionally, the average number of families per family household and the average number of people per other multi-person household are assumed to remain constant at 2006 levels. At the national level:
- the average number of families per family household is assumed to remain constant at 1.041
- the average number of people per other multi-person household is assumed to remain constant at 2.600.
Regional projections
Family and household projections for regional council areas are calculated by combining projections for territorial authority areas (TAs), or parts of TAs when a TA is split between regions. Of the 73 TAs, 8 TAs are split over two or more regions, while the remaining 65 TAs are completely within one region.
LATRs are calculated at TA level, except for Franklin District where LATRs are calculated separately for the parts of the district in the Auckland and Waikato regions. For other TAs which are split between regions, LATRs for that TA are applied to population projections for each part of the TA.
Those variables which cannot be obtained by summation, such as average family size and average household size, are recalculated for regions after combining the TA projections.
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2006-base to 2031 (released July 2009)
Alternative series
Three alternative subnational family and household projection series (designated low, medium and high) have been produced for each area using different population projection series (with different fertility, mortality and migration assumptions). One set of living arrangement type assumptions has been used for all three series. The terms 'low', 'medium' and 'high' do not correspond to probabilities, but merely indicate the combination of assumptions.
The medium projection series uses the medium series of the 2006-base subnational population projections (released 3 December 2007), which assumes medium fertility, medium mortality and medium net migration for each area. The medium subnational family and household projection series is consistent with series 5B of the 2006-base national family and household projections (released 8 December 2008) and series 5 of the 2006-base national population projections (released 24 October 2007).
The low projection series uses low fertility, high mortality and low net migration for each area. The high projection series uses high fertility, low mortality and high net migration for each area. The low and high projection series allow users to assess the impact of changing population size and structure on the number and type of families and households. The low and high series have been formulated to give plausible alternative scenarios for each area rather than at any collective geographical level. Neither series is consistent with any of the alternative series of the 2006-base national family and household projections.
Users can make there own judgement as to which projection series is/are most suitable for their purposes. However, at the time of release, Statistics New Zealand considers the medium projection series the most suitable for assessing future family and household changes.
Fertility
The assumed fertility rates are based on the registered births for each area during the period 2006–07 and change consistent with the medium fertility variant of the 2006-base national population projections.
Under the medium fertility assumption, the total fertility rate at the national level is assumed to increase from 1.99 births per woman in 2006 to 2.11 in 2008, decrease to 1.90 in 2026, and then remain constant. The assumed total fertility rate in 2007–11 ranges from 1.40 births per woman for Queenstown-Lakes district to 3.10 for Wairoa district.
The high and low fertility assumptions for each area are for a total fertility rate for each five-year period ±0.1 births per woman from the medium assumption.
A sex ratio at birth of 105.5 males per 100 females is assumed, based on the historical annual average at the national level.
Mortality
The assumed mortality rates for each area are based on the registered deaths for each area during the period 2002–06 and change consistent with the medium mortality variant of the 2006-base national population projections.
Under the medium mortality assumption, life expectancy at birth at the national level is assumed to increase from 78.2 years for males and 82.2 years for females in 2005–07 to 82.5 years for males and 86.2 years for females in 2031. The assumed life expectancy at birth in 2007–11 ranges from 74.3 years for males and 78.4 years for females for Wairoa district to 82.7 years for males and 86.5 years for females for Queenstown-Lakes district.
The low and high mortality assumptions for each area are for a life expectancy at birth for each five-year period ±0.5 years from the medium assumption.
Migration
Migration at the subnational level has both an internal (to/from other areas of New Zealand) and an external (to/from overseas) component, although these separate components are difficult to quantify. The assumed net migration for each area is based on a consideration of observed net migration during each five-year period from 1981 to 2006, the capacity of the area for further growth (for areas with net inflow), whether historical outflows can be sustained (for areas with net outflow), the desirability of the area to new migrants, and information available from and about local authorities relating to current and future developments which may affect population change.
Under the medium migration assumption, net migration at the national level is assumed to be 46,000 in 2007–11 and 50,000 in each subsequent five-year period. Of the 73 territorial authority areas, 59 are assumed to have the same net migration level in each five-year period between 2006 and 2031. The remaining areas are assumed to have differing net migration levels between 2006 and 2011 compared with subsequent periods. Differing levels are generally assumed for areas susceptible to changes in external migration, such as university cities, which have attracted large numbers of overseas students in recent years, and areas where constant net outflows are considered unsustainable.
The low and high net migration assumptions are chosen to represent plausible alternative migration scenarios for each area rather than at the collective national level. The age-sex patterns of net migration for each area are based on observed intercensal net migration patterns during 1981–2006.
Living arrangement type rates (LATRs)
One LATR variant is used for all three subnational family and household projection series. This assumes that LATRs will change linearly between 2006 and 2031, based on an assessment of observed trends between 1986 and 2006, and likely future trends, by sex and five-year age group. The LATRs are constrained so that the medium series of the Subnational Family and Household Projections sums to series 5B of the 2006-base national family and household projections (released 8 December 2008) for population (by living arrangement type, five-year age group and sex), for families (by family type) and for households (by household type). While assumed trends in living arrangement type rates do vary by area, they are generally consistent with assumed trends at the national level.
Additionally, the average number of families per family household and the average number of people per other multi-person household are assumed to remain constant at 2006 levels. At the national level:
- the average number of families per family household is assumed to remain constant at 1.041
- the average number of people per other multi-person household is assumed to remain constant at 2.600.
Regional projections
Family and household projections for regional council areas are calculated by combining projections for territorial authority areas (TAs), or parts of TAs when a TA is split between regions. Of the 73 TAs, 8 TAs are split over two or more regions, while the remaining 65 TAs are completely within one region.
LATRs are calculated at TA level, except for Franklin District where LATRs are calculated separately for the parts of the district in the Auckland and Waikato regions. For other TAs which are split between regions, LATRs for that TA are applied to population projections for each part of the TA.
Those variables which cannot be obtained by summation, such as average family size and average household size, are recalculated for regions after combining the TA projections.
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Output Variables
Output variables are pieces of individual information that can be extracted from the survey/output data. Often output variables can be cross tabulated with other output variables, for example sales by industry classification. The list below contains all current and past output variables which have been released for this survey/output.
Population Projections
Population by age and sex
Population change
Age-sex distribution of the population
Dependency ratios
Births
Deaths
Natural increase (births minus deaths)
Median age (half of the population is younger, and half older, than this age)
Ethnic Population Projections
Population by age and sex
Population change
Age-sex distribution of the population
Ethnic share of total population
Births
Deaths
Natural increase (births minus deaths)
Median age (half of the population is younger, and half older, than this age)
Family and Household Projections
Families by family type
Family change by family type
Families with dependent children by family type
Households by household type
Household change by household type
Age-sex distribution of the population in living arrangement type
Average family size by family type
Average household size by household type
Household size distribution by household type
Labour Force Projections
Labour force by age and sex
Labour force change
Percentage of population aged 15 years and over who are in the labour force
Age-sex distribution of the labour force
Median age (half of the labour force is younger, and half older, than this age) |
Changes in Output Variables over time
Guide to Interpreting Data
Summary of Changes to Survey/Output ..
| 1953 | First set of national Māori population projections produced. The base population was the estimated de facto population of Māori ethnicity of New Zealand at 31 March 1952. |
| 1988 | Local Government Amendment Act No 3 provides for the constitution of 14 regional councils. The regional council areas cover every territorial authority area in New Zealand with the exception of Chatham Islands Territory (formerly Chatham Islands County). These replaced 22 local government regions. |
| 1 November 1989 | Local government reorganisation creates 74 territorial authority areas. These replaced 213 local authorities. |
| 1991 | Census labour force question changed so that the census labour force will relate more closely to the definition used in the Household Labour Force Survey (HLFS).
Classification of urban areas revised into a three-part classification consisting of main, secondary and minor urban areas differentiated by population size. |
| 1 July 1992 | The number of regions increased from 14 to 16 following boundary reorganisation in the northern South Island. |
| 1993 | First set of national Pacific population projections produced. The base population was the census usually resident population count of Pacific ethnic group (but excluding people with Māori ethnicity) of New Zealand at 5 March 1991. |
| 1994 | First set of regional Māori population projections produced. The base population was the census usually resident population count of Māori ethnicity of each area at 5 March 1991. |
| September 1995 | New birth and death registration forms introduced carrying a revised question on ethnicity. Previously the ethnic questions asked for the degree of Māori or "Pacific Island" blood, if any. The new ethnic question instructs the respondent to "tick as many circles as needed to show which ethnic group(s)...". This resulted in a number of changes:
- the ethnic concept is now self-identified ethnicity (previously Māori and Pacific respondents were classified by their 'degree of blood')
- ethnic vital statistics are now available for a wider range of ethnic groups (previously information was only sought for Māori and Pacific groups)
- ethnic data is now directly available for newborn babies and the deceased (in both cases this was previously derived from their parent's ethnicity)
- multiple response to the ethnicity question is now possible (previously the degree of Māori or Pacific blood, but not both, could be identified)
- non-response to the ethnicity question can now be quantified.
See also Births and Deaths Profiles. |
| 1996 | Population concept for all demographic estimates, projections and indices changed from 'de facto' to 'resident'. Population estimates based on the de facto population concept (the estimated de facto population) include visitors from overseas, but made no adjustments for net census undercount or residents temporarily overseas. Population estimates based on the resident population concept (the estimated resident population) include adjustments for net census undercount and residents temporarily overseas, but exclude overseas visitors.
The reference date for projections is shifted from 31 March to 30 June. |
| 1998 | First set of national Asian population projections produced. The base population was the estimated resident population of Asian ethnic group of New Zealand at 30 June 1996. |
| 2003 | First set of national European population projections produced. The base population was the estimated resident population of European ethnic group of New Zealand at 30 June 2001.
A new 'propensity' method used to produce national family and household projections, superseding the 1996-base national household projections which used a 'household head' method. The new series include, for the first time, projections of families by broad family type and projections of broad household types.
First set of subnational Pacific, Asian and European population projections produced. The base population was the estimated resident population of each ethnic group of each area at 30 June 2001. |
| 2004 | A new 'propensity' method used to produce subnational family and household projections, superseding the 1996-base subnational household projections which used a 'household head' method. The new series include, for the first time, projections of families by broad family type and projections of broad household types. |
Usage and Limitations of the Data ..Demographic projections are designed to meet both short-term and long-term planning needs, but are not designed to be exact forecasts or to project specific annual variation. Demographic projections are based on assumptions about future fertility, mortality, migration, inter-ethnic mobility, living arrangement type and labour force participation patterns of the population. Although the assumptions are carefully formulated to represent future trends, they are subject to uncertainty. Therefore, the projections should be used as guidelines and an indication of the overall trend, rather than as exact forecasts.
Demographic projections should not be confused with economic forecasts. Changes in the number of people, families and households do not necessarily relate to the social and economic well-being of an area. The number of people, families and households may change independently of local economic factors.
The projections do not take into account non-demographic factors (eg war, catastrophes, major government and business decisions, changes to the ethnic classification) which may invalidate the projections. Demographic trends are monitored regularly, and when it is necessary, the projections are revised to reflect new trends and to maintain their relevance and usefulness.
A person may identify with more than one ethnicity. At the 2006 Census, there were 3,860,163 people who gave an ethnic response and 167,784 people who gave no specific ethnic response (based on the census usually resident population count). Of those responding, 400,428 people identified with more than one ethnicity. These included people identifying with, for example, Māori and New Zealand European, or with Samoan and Tongan, or with New Zealander and English and Irish. People who identify with more than one ethnicity are included in each ethnic population. Therefore, the ethnic population projections are not mutually exclusive.
Household numbers should not be confused with building activity or dwelling numbers. Households refer to private dwellings that are usually occupied by a person or group of people. Households therefore exclude non-private dwellings, unoccupied dwellings and dwellings which are not the usual residence of people (eg holiday homes, second homes).
Related Data Sources ..Population Estimates
Sampling Errors ..
Non-sampling errors
Caveats on Release ..Demographic projections are designed to meet both short-term and long-term planning needs, but are not designed to be exact forecasts or to project specific annual variation. Demographic projections are based on assumptions about future fertility, mortality, migration, inter-ethnic mobility, living arrangement type and labour force participation patterns of the population. Although the assumptions are carefully formulated to represent future trends, they are subject to uncertainty. Therefore, the projections should be used as guidelines and an indication of the overall trend, rather than as exact forecasts.
Demographic projections should not be confused with economic forecasts. Changes in the number of people, families and households do not necessarily relate to the social and economic well-being of an area. The number of people, families and households may change independently of local economic factors.
The projections do not take into account non-demographic factors (eg war, catastrophes, major government and business decisions, changes to the ethnic classification) which may invalidate the projections. Demographic trends are monitored regularly, and when it is necessary, the projections are revised to reflect new trends and to maintain their relevance and usefulness.
A person may identify with more than one ethnicity. At the 2006 Census, there were 3,860,163 people who gave an ethnic response and 167,784 people who gave no specific ethnic response (based on the census usually resident population count). Of those responding, 400,428 people identified with more than one ethnicity. These included people identifying with, for example, Māori and New Zealand European, or with Samoan and Tongan, or with New Zealander and English and Irish. People who identify with more than one ethnicity are included in each ethnic population. Therefore, the ethnic population projections are not mutually exclusive.
Household numbers should not be confused with building activity or dwelling numbers. Households refer to private dwellings that are usually occupied by a person or group of people. Households therefore exclude non-private dwellings, unoccupied dwellings and dwellings which are not the usual residence of people (eg holiday homes, second homes).
Customised Output
National Population Projections:
Summary table of population and selected demographic characteristics
Population by five-year age group and sex
Population by single year of age and sex
Subnational Population Projections:
Summary table of population and selected demographic characteristics
Population by five-year age group and sex
Catalogue & Reference Numbers
Other Comments
Classification(s) used
Classifications |
Classification Versions |
Classification Type |
SEX - Sex - New Zealand Standard Classification |
V1.0 |
NZ Standard |
AGEGPS - Age - 5 Year Groupings |
V1.0 |
Standard |
ETHNIC05 - Ethnicity New Zealand Standard Classification 2005 |
V1.0 |
Standard |
AGE - Age - New Zealand Standard Classification |
V1.0 |
NZ Standard |
FAMTYPE99 - Family Type - New Zealand Standard Classification 1999 |
V1.0 |
NZ Standard |
HHCOMP99 - Household Composition - New Zealand Standard Classification 1999 |
V1.0 |
NZ Standard |
TA04 - Territorial Authority 2004 |
V2.0 |
NZ Standard |
REGC04 - Regional Council 2004 |
V1.0 |
NZ Standard |
UA04 - Urban Area 2004 |
V1.0 |
NZ Standard |
TA06 - Territorial Authority 2006 |
V2.0 |
NZ Standard |
REGC06 - Regional Council 2006 |
V1.0 |
NZ Standard |
Glossary of Terms
| Term | Description |
| Asian population | People who identify with an Asian ethnicity (eg Chinese, Indian, Korean) with or without other ethnicities.
Because ethnicity is self-perceived, people can identify with an Asian ethnicity even though they are not descended from Asian ancestors. Conversely, people may choose to not identify with an Asian ethnicity even though they are descended from Asian ancestors. Ethnicity is not the same as birthplace. |
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| Assumption | Statement about a future course of behaviour (eg fertility, mortality, net migration, living arrangement type, labour force participation) from which demographic projections (eg of population, families, households, labour force) are derived. |
| Base population | The starting population, usually distributed by age and sex, from which population estimates and projections are derived. The base population for all 2006-base national and subnational population estimates and projections is the estimated resident population at 30 June 2006. |
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| Cohort component method | In deriving population projections, the base population is projected forward by calculating the effect of deaths and migration within each age-sex group according to specified mortality and migration assumptions. New birth cohorts are generated by applying specified fertility assumptions to the female population of childbearing age. |
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De facto population concept
| A statistical basis for a population in terms of those present in a given area at a given time. The census night population count is a census measure of the de facto population concept, and the estimated de facto population is a demographic measure of the de facto population concept. |
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| Estimated resident population | An estimate of all people who usually live in a given area at a given date.
The estimated resident population of New Zealand includes all residents present in New Zealand and counted by the census (census usually resident population count), residents who are temporarily overseas (who are not included in the census), and an adjustment for residents missed or counted more than once by the census (net census undercount). Visitors from overseas are excluded.
For a subnational area the estimate excludes visitors from overseas and elsewhere in New Zealand (people who do not usually live in that area), but includes residents of that area who are temporarily elsewhere on census night (people who usually live in that area but are absent).
The estimated resident population at a given date after census is calculated by updating the base population for births, deaths and net migration (arrivals less departures) of residents of that area during the period between census night and the given date.
National population estimates are produced quarterly (reference dates at 31 March, 30 June, 30 September and 31 December) and subnational population estimates are produced annually (reference date at 30 June). |
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| Ethnicity | An ethnic group is made up of people who have some or all of the following characteristics:
- a common proper name
- one or more elements of common culture which need not be specified, but may include religion, customs or language
- unique community of interests, feelings and actions
- a shared sense of common origins or ancestry, and
- a common geographic origin.
This definition is based on the work of A Smith (1986) 'The Ethnic Origins of Nations'.
Ethnicity is self-perceived and people can belong to more than one ethnic group. People can identify with an ethnicity even though they are not descended from ancestors with that ethnicity. Conversely, people may choose to not identify with an ethnicity even though they are descended from ancestors with that ethnicity. Ethnicity is not the same as birthplace.
In the Census of Population and Dwellings, ethnicity is identified by the person completing the census form. In the case of births and deaths, ethnicity is identified by the person completing the registration form. For births this is usually the parent(s), while for deaths this is most likely to be the funeral director (on the advice of a family member). |
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| European population | People who identify with a European ethnicity (eg New Zealand European, English, Dutch) with or without other ethnicities.
Because ethnicity is self-perceived, people can identify with a European ethnicity even though they are not descended from European ancestors. Conversely, people may choose to not identify with a European ethnicity even though they are descended from European ancestors. Ethnicity is not the same as birthplace. |
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| Family | A couple, with or without child(ren), or one parent with child(ren), usually living together in a household. Related people, such as siblings, who are not in a couple or parent-child relationship, are therefore excluded from this definition. |
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| Household | Either one person usually living alone, or two or more people usually living together and sharing facilities (eg eating facilities, cooking facilities, bathroom and toilet facilities, a living area), in a private dwelling. |
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| Householder | A reference person for a household based on who fills out the census dwelling form. |
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| Householder rate | The proportion of the population who are householders, usually disaggregated by age and sex. |
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| Inter-ethnic mobility | People changing their ethnic identification over time. This may reflect a person's cultural affiliations changing over time.
Inter-ethnic mobility may occur when different people respond to the ethnicity question. For example, the ethnicity of babies and young children is usually identified by their parents. However, in a later census when these children are old enough to complete their own forms, they will decide for themselves which ethnicity they identify with. This may differ from the ethnicity identified by their parents.
Inter-ethnic mobility can also occur when different ethnicities are reported in different collections (eg birth registration form, death registration form, census form) for a person. |
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| Labour force | People aged 15 years and over who regularly work for one or more hours per week for financial gain, or work without pay in a family business, or are unemployed and actively seeking part-time or full-time work. |
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| Labour force participation rate | The proportion of the population in the labour force, usually disaggregated by age and sex. |
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| Life expectancy (expectation of life) | The average length of life remaining at a given age. As derived from a period life table, it assumes that a person experiences the age-specific mortality rates of a given period from the given age onwards. |
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| Living arrangement type | The usual family and household role of a person based on a combination of individual, family, household and dwelling information. As used in family and household projections, all people are allocated to one of 11 living arrangement types:
- Partner in couple without children family
- Other person with couple without children family
- Partner/parent in two-parent family
- Child in two-parent family
- Other person with two-parent family
- Parent in one-parent family
- Child in one-parent family
- Other person with one-parent family
- Person in other multiperson household
- Person in one-person household
- Person in non-private dwelling
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| Living arrangement type rate | The proportion of the population in a living arrangement type, usually disaggregated by age and sex. |
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| Māori population | People who identify with the Māori ethnicity with or without other ethnicities.
Because ethnicity is self-perceived, people can identify with Māori ethnicity even though they are not descended from Māori ancestors. Conversely, people may choose to not identify with Māori ethnicity even though they are descended from Māori ancestors. Ethnicity is not the same as birthplace. |
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| Pacific population | People who identify with a Pacific ethnicity (eg Samoan, Tongan, Fijian) with or without other ethnicities.
Because ethnicity is self-perceived, people can identify with a Pacific ethnicity even though they are not descended from Pacific ancestors. Conversely, people may choose to not identify with a Pacific ethnicity even though they are descended from Pacific ancestors. Ethnicity is not the same as birthplace. |
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| Projection | Estimate of the future demographic characteristics of a population, families, households or labour force based on an assessment of past trends and assumptions about the future course of demographic behaviour (eg fertility, mortality, net migration, living arrangement type, labour force participation). |
| Propensity method | A method of projecting the number of families and households based on the proportion of a population, usually disaggregated by age and sex, who live in different living arrangement types. Living arrangement type rates (or propensities) are applied to population projections to give projections of the population in different living arrangement types. These projections are subsequently aggregated to give projections of families (by broad family type) and households (by broad household type). |
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| Resident population concept | A statistical basis for a population in terms of those who self-identify that they usually live in a given area at a given time. The census usually resident population count is a census measure of the resident population concept, and the estimated resident population is a demographic measure of the resident population concept. |
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| Subnational | Geographical units of a country (eg area units, territorial authorities, regional councils, urban areas) whose boundaries are defined for administrative, legal or statistical purposes. |
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| Total fertility rate | The average number of live births that a woman would have during her life if she experienced the age-specific fertility rates of a given period (usually a year). It excludes the effect of mortality. |
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| Total paternity rate | As used in ethnic population projections, the average number of live births that a man of a given ethnicity would have with women of other ethnicities during his life if he experienced the age-specific paternity rates of a given period (usually a year). It excludes the effect of mortality.
- Māori population – the rate applied to the Māori male population to produce the number of births between Māori males partnered with non-Māori females.
- Pacific population – the rate applied to the Pacific male population to produce the number of births between Pacific males partnered with non-Pacific females.
- Asian population – the rate applied to the Asian male population to produce the number of births between Asian males partnered with non-Asian females.
- European population – the rate applied to the European male population to produce the number of births between European males partnered with non-European females.
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Liability
Statistics New Zealand gives no warranty that the information or data supplied contains no errors. However, all care and diligence has been used in processing, analysing and extracting the information. Statistics New Zealand shall not be liable for any loss or damage suffered by the customer consequent upon the use directly, or indirectly, of the information supplied in this product.
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