Term	Tornqvist Index and other Log-change Index Numbers
Synonym
Related Term
Source of Definition
Short Definition
Statistical Activity	Inflation measures

Definition
Index numbers are measures of relative change which are usually based on ratios. Log-change index numbers, like Tornqvist, are based on the natural logarithms of those ratios. The Tornqvist index is not often used as it requires the use of quantities purchased in the current period.
(c.f. Laspeyres, Paasche, Fisher Ideal, Marshall-Edgeworth, indexes)


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