There is generally a need to deal with quality change and new goods in the consumer price index due to the underlying dynamic item universe. Traditionally axiomatic tests are defined for a fixed universe. We propose five tests explicitly formulated for a dynamic item universe, and motivate them both from the perspectives of a cost-of-goods index and a cost-of-living index. None of the indices that are currently available for making use of scanner data satisfies all the tests at the same time. The set of tests provides a rigorous diagnostic for whether an index is completely appropriate in a dynamic item universe, as well as pointing towards the directions of possible remedies. We thus outline a large index family that potentially can satisfy all the tests.
De Haan, J. and F. Krsinich. 2014. “Scanner Data and the Treatment of Quality Change in Nonrevisable Price Indexes.” Journal of Business & Economic Statistics 32: 341–358. Doi: https://doi.org/10.1080/07350015.2014.880059.
Diewert, E.W. 1999. “Axiomatic and Economic Approaches to International Comparisons.” In International and Interarea Comparisons of Income, Output, and Prices, edited by A. Heston and R.E. Lipsey, 13–87. Studies in Income and Wealth, Vol. 61. Chicago: University of Chicago Press.
Fisher, I. 1922. The Making of Index Numbers. Boston: Houghton-Mifflin.
Geary, R.C. 1958. “A Note on Comparisons of Exchange Rates and Purchasing Power Between Countries.” Journal of the Royal Statistical Society, Series A 121: 97–99. Available at: https://www.jstor.org/stable/pdf/2342991.pdf (accessed June 2019).