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Consumer prices for apparel were adjusted downward more than prices for any other major group of items in the new CPI research series. On average, apparel inflation was reduced by about a percentage point per year in 1978-98 using the new research index.
Most of the inflation rates for major groups of consumer items in 1978-98 were lowered in the new research series, but the reduction was by far the greatest in apparel. For example, the research series shaved 0.49 percentage point per year off the measured growth of food prices, 0.57 percentage point off of housing prices, and 0.62 percentage point off of entertainment prices. In contrast, it knocked 1.10 percentage points off of apparel prices.
BLS has made numerous improvements to the CPI over the years, which have increased the accuracy of the index; however, the official historical price indexes are not adjusted to reflect the improvements. The research series attempts to answer the question, "What would have been the measured rate of inflation from 1978 forward had the methods currently used in calculating the Consumer Price Index been in use since 1978?"
CPI data are produced by the BLS Consumer Price Index program. More information on the CPI research series can be found in "CPI research series using current methods, 1978-98," by Kenneth J. Stewart and Stephen B. Reed, Monthly Labor Review preprint, June 1999. It is important to note that the CPI research series has certain limitations and that it is subject to revision. Growth rates reflect December-to-December changes. The growth rate for entertainment in the chart refers to 1978-97, as entertainment was dropped as a major group in December 1997.
Bureau of Labor Statistics, U.S. Department of Labor, The Economics Daily, Apparel prices adjusted downward the most in new research series at https://www.bls.gov/opub/ted/1999/jun/wk4/art02.htm (visited June 07, 2023).