The Consumer Price Index (CPI) relies on a sample of households in different metropolitan areas to represent urban households across the nation. Historically, this sample of areas has been based on the Decennial Census, which produces counts of the population in all metropolitan areas. Periodically, the CPI program needs to adjust the sample to reflect changes in the distribution of the population across the country. The CPI program is updating its sample to reflect the data from the 2010 Decennial Census on the distribution of the urban population.
Under the previous design, indexes were published for Pittsburgh, PA; Cincinnati-Hamilton, OH-KY-IN; Cleveland-Akron, OH; Milwaukee-Racine, WI; and Portland-Salem, OR-WA. Because they did not meet a population threshold, they will not be published under the new design. In addition, the index for Kansas City, MO-KS will no longer be published because it was not selected as part of the sample.
While we cannot tell customers which area to use, there are several options to replace a discontinued area. Indexes for areas smaller than the nation have smaller sample sizes, and are therefore subject to larger sampling errors and exhibit greater volatility than national indexes. Thus in general BLS recommends that users consider one of the national indexes. This is particularly true for use in escalation clauses. Additional information on using the CPI for escalation is available online at How to Use the Consumer Price Index for Escalation.
The nine Census Divisions and Riverside, CA will have a base period of December 2017=100.
A full list of name and geographic changes is available online at 2018 Geographic Revision Area Concordance.
Yes, even if the precise boundaries of an area have changed.
Twelve-month percent changes will be available with December 2018 data for cities published for even months and with January 2019 data for cities published for odd months (including Riverside). Over-the-year changes for Washington D.C. will be available with January 2018 data and with February 2018 data for Baltimore. Twelve-month percent changes will be available with December 2018 data for the Census Divisions.
Yes, the semi-annual data will be comparable.
Two resources are available that provide additional information. A short overview of the revision is available in the Consumer Price Index Geographic Revision for 2018 notice and more comprehensive information is available in Monthly Labor Review article The 2018 revision of the Consumer Price Index geographic sample.