Fisher Ideal Index
The Fisher ideal index is a superlative index number that aggregates many individual prices or quantities into a single measure of overall change by taking the geometric mean of the Laspeyres (base-weighted) and Paasche (current-weighted) indices. Proposed by Irving Fisher in his 1922 treatise as the 'ideal' formula because it passes a battery of desirable axiomatic tests, it was later shown by W. Erwin Diewert to be exact for a flexible (quadratic) aggregator, giving it both an axiomatic and an economic-theoretic justification. It is the index of choice when a measure must satisfy the time-reversal and factor-reversal tests exactly.
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Sources
- Fisher, I. (1922). The Making of Index Numbers: A Study of Their Varieties, Tests, and Reliability. Boston: Houghton Mifflin. ISBN: 9780678006597
- Diewert, W. E. (1976). Exact and superlative index numbers. Journal of Econometrics, 4(2), 115–145. DOI: 10.1016/0304-4076(76)90009-9 ↗
How to cite this page
ScholarGate. (2026, June 22). Fisher Ideal Index (Superlative Price and Quantity Index). ScholarGate. https://scholargate.app/en/economics/fisher-ideal-index
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