“Chain drift” in the Chained Consumer Price Index: 1999–2017

This article employs circularity and unity tests, as well as multilateral index comparisons, to measure the existence and extent of “drift” in the Chained Consumer Price Index for All Urban Consumers (C-CPI-U). It applies various formulas to real data that were used to calculate the Consumer Price Index during the period from December 1999 to December 2017. Overall, the findings show only small amounts of chain drift in the C-CPI-U over the study period. This article presents the most comprehensive study to date from the U.S. Bureau of Labor Statistics (BLS) to document the extent of chain drift in the Chained Consumer Price Index for All Urban Consumers (C-CPI-U).