The U.S. Consumer Price Index
(CPI) is a time series
measure of the price level of consumer goods and services. The Bureau of Labor Statistics
, which started the statistic in 1919, publishes the CPI on a monthly basis. The CPI is calculated by observing price changes among a wide array of products in urban areas and weighing these price changes by the share of income consumers spend purchasing them. The resulting statistic, measured as of the end of the month for which it is published, serves as one of the most popular measures of United States inflation
; however, the CPI focuses on approximating a cost-of-living index
not a general price index
The CPI can be used to track changes in prices of all goods and services purchased for consumption by urban households, i.e., of the consumer basket. User fees (such as water and sewer service) and sales and excise taxes paid by the consumer are also included. Income taxes and investment items (like stocks, bonds, life insurance, and homes) are not included. The index measures inflation faced by consumers who live in urban areas designated by the U.S. Bureau of the Census
The base period used for the current U.S. CPI is 1982-4.
BLS calculates the CPI for two population groups, one consisting only of wage earners and clerical workers and the other consisting of all urban consumers. In addition, a Core CPI, which excludes volatile food and energy prices and a Chained CPI are also widely used measures of consumer......