The Consumer Price Index for All Urban Consumers (CPI-U), the headline CPI series, tracks average price change for goods and services bought by urban consumers. It is published monthly by the Bureau of Labor Statistics (BLS) from about 80000 prices in 75 areas. It covers over 90% of the population, while CPI-W covers wage earners and C-CPI-U allows substitution.
It measures out of pocket price including sales and excise taxes, with a reference base set at 100. It is not a full cost of living measure and does not compare price levels across areas. It excludes houses, stocks, income taxes and rural populations and reflects a basket, not any household.
Prices are collected during the entire month across 3 pricing periods, with fuels priced monthly in all 75 areas. Housing comes from a 6-panel survey, each panel priced 2 times yearly using 6-month rent ratios. The sample covers about 6000 housing units and 23000 shops.
It is released monthly mid-month after the reference month, embargoed until 8:30 AM Eastern Time. Each release includes a news release with tables and a database covering 4 price series and area detail. Most reported are 1-month adjusted change for short trends and 12-month unadjusted change.
CPI-U and CPI-W stay final when issued and change only if an error is found. Adjusted series revise for 5 years with yearly factors, while C-CPI-U stays preliminary for 10 to 12 months. Analysts use adjusted change for short trends and unadjusted change for escalation, since adjusted series revise. Escalation agreements are advised to use unadjusted data.
Weights reflect average urban spending and reset once each year, so heavy groups drive the headline most. The index has 8 major groups, and energy moves sharply even without a weight shown here.
All items less food and energy gets attention as underlying inflation without volatile food and energy. Heavy groups shape the headline, while light groups can still move the other way in any month.
Key point: The index only approximates a cost of living measure and reflects an average basket, not any household. Area indexes track change since the base period, not price levels, and exclude houses, stocks and income taxes.
