Scanner Data, Time Aggregation and the Construction of Price Indexes
The impact of weekly, monthly and quarterly time aggregation on estimates of price change is examined for nineteen different supermarket item categories over a fifteen month period using scanner data. We find that time aggregation choices (the choice of a weekly, monthly or quarterly unit value concept for prices) have a considerable impact on estimates of price change. When chained indexes are used, the difference in price change estimates can be huge, ranging from 0.28% to 29.73% for a superlative (Fisher) index and an incredible 14.88% to 46,463.71% for a non-superlative (Laspeyres) index. The results suggest that traditional index number theory breaks down when weekly data with severe price bouncing are used, even for superlative indexes. Monthly and (in some cases even) quarterly time aggregation were found to be insufficient to eliminate downward drift in superlative indexes. In order to eliminate chain drift, multilateral index number methods are adapted to provide drift free measures of price change.
|Date of creation:||22 Sep 2009|
|Date of revision:||22 Sep 2009|
|Contact details of provider:|| Web page: http://www.economics.ubc.ca/|
Please report citation or reference errors to , or , if you are the registered author of the cited work, log in to your RePEc Author Service profile, click on "citations" and make appropriate adjustments.:
- Mary F. Kokoski & Brent R. Moulton & Kimberly D. Zieschang, 1999. "Interarea Price Comparisons for Heterogeneous Goods and Several Levels of Commodity Aggregation," NBER Chapters, in: International and Interarea Comparisons of Income, Output, and Prices, pages 123-169 National Bureau of Economic Research, Inc.
- William J. Hawkes & Frank W. Piotrowski, 2003. "Using Scanner Data to Improve the Quality of Measurement in the Consumer Price Index," NBER Chapters, in: Scanner Data and Price Indexes, pages 17-38 National Bureau of Economic Research, Inc.
- Robert C. Feenstra & Matthew D. Shapiro, 2001.
"High-Frequency Substitution and the Measurement of Price Indexes,"
NBER Working Papers
8176, National Bureau of Economic Research, Inc.
- Robert C. Feenstra & Matthew D. Shapiro, 2003. "High-Frequency Substitution and the Measurement of Price Indexes," NBER Chapters, in: Scanner Data and Price Indexes, pages 123-150 National Bureau of Economic Research, Inc.
- Reinsdorf, Marshall B, 1999. "Using Scanner Data to Construct CPI Basic Component Indexes," Journal of Business & Economic Statistics, American Statistical Association, vol. 17(2), pages 152-60, April.
- W. Erwin Diewert, 1995. "Axiomatic and Economic Approaches to Elementary Price Indexes," NBER Working Papers 5104, National Bureau of Economic Research, Inc.
- Diewert, W. E., 1976. "Exact and superlative index numbers," Journal of Econometrics, Elsevier, vol. 4(2), pages 115-145, May.
- W. Erwin Diewert, 1996.
"Axiomatic and Economic Approaches to International Comparisons,"
NBER Working Papers
5559, National Bureau of Economic Research, Inc.
- W. Erwin Diewert, 1999. "Axiomatic and Economic Approaches to International Comparisons," NBER Chapters, in: International and Interarea Comparisons of Income, Output, and Prices, pages 13-107 National Bureau of Economic Research, Inc.
- Caves, Douglas W & Christensen, Laurits R & Diewert, W Erwin, 1982. "Multilateral Comparisons of Output, Input, and Productivity Using Superlative Index Numbers," Economic Journal, Royal Economic Society, vol. 92(365), pages 73-86, March.
- Hill, Robert J., 2006. "Superlative index numbers: not all of them are super," Journal of Econometrics, Elsevier, vol. 130(1), pages 25-43, January.
- Kravis, Irving B, 1984. "Comparative Studies of National Incomes and Prices," Journal of Economic Literature, American Economic Association, vol. 22(1), pages 1-39, March.
- Drechsler, Laszlo, 1973. "Weighting of Index Numbers in Multilateral International Comparisons," Review of Income and Wealth, International Association for Research in Income and Wealth, vol. 19(1), pages 17-34, March.
- Diewert, W Erwin, 1978. "Superlative Index Numbers and Consistency in Aggregation," Econometrica, Econometric Society, vol. 46(4), pages 883-900, July.
When requesting a correction, please mention this item's handle: RePEc:ubc:bricol:erwin_diewert-2009-48. See general information about how to correct material in RePEc.
For technical questions regarding this item, or to correct its authors, title, abstract, bibliographic or download information, contact: (Maureen Chin)
If references are entirely missing, you can add them using this form.