The Consumer Price Index for Boston is published bi-monthly. The Consumer Price Index (CPI) is a measure of the average change in prices over time in a fixed market basket of goods and services. The Bureau of Labor Statistics publishes CPIs for two population groups: (1) a CPI for All Urban Consumers (CPI-U) which covers approximately 93 percent of the total U.S. population and (2) a CPI for Urban Wage Earners and Clerical Workers (CPI-W) which covers approximately 29 percent of the total U.S. population. The CPI-U includes, in addition to wage earners and clerical workers, groups such as professional, managerial, and technical workers, the self-employed, short-term workers, the unemployed, and retirees and others not in the labor force.

The CPI is based on prices of food, clothing, shelter, fuels, transportation fares, charges for doctors' and dentists' services, drugs, and the other goods and services that people buy for day-to-day living. Each month, prices are collected in 75 urban areas across the country from about 6,000 housing units and approximately 22,000 retail establishments—department stores, supermarkets, hospitals, filling stations, and other types of stores and service establishments. All taxes directly associated with the purchase and use of items are included in the index.

The index measures price changes from a designated reference date; for most of the CPI-U the reference base is 1982-84 equals 100. An increase of 7 percent from the reference base, for example, is shown as 107.000.  Alternatively, that relationship can also be expressed as the price of a base period market basket of goods and services rising from $100 to $107. For further details see the CPI home page on the internet at www.bls.gov/cpi and the CPI section of the BLS Handbook of Methods available on the internet at www.bls.gov/opub/hom/cpi/.

In calculating the index, price changes for the various items in each location are averaged together with weights that represent their importance in the spending of the appropriate population group. Local data are then combined to obtain a U.S. city average. Because the sample size of a local area is smaller, the local area index is subject to substantially more sampling and other measurement error than the national index. In addition, local indexes are not adjusted for seasonal influences. As a result, local area indexes show greater volatility than the national index, although their long-term trends are quite similar. NOTE: Area indexes do not measure differences in the level of prices between cities; they only measure the average change in prices for each area since the base period.

The Boston-Cambridge-Newton, MA-NH Core Based Statistical Area covered in this release is comprised of Essex, Middlesex, Norfolk, Plymouth, Suffolk Counties in Massachusetts and Rockingham and Strafford Counties in New Hampshire.

Information in this release will be made available to individuals with sensory impairments upon request. Voice phone: (202) 691-5200; Telecommunications Relay Service: 7-1-1.