<P> The U.S. Consumer Price Index (CPI) is a set of consumer price indices calculated by the U.S. Bureau of Labor Statistics (BLS). To be precise, the BLS routinely computes many different CPIs that are used for different purposes . Each is a time series measure of the price of consumer goods and services . The BLS publishes the CPI monthly . </P> <P> The BLS started the statistic in 1919 . It currently computes thousands of consumer price indices, beginning with monthly average prices for each of 8,018 category - area combinations (211 categories of consumption items in 38 urban geographical areas). They also track how much of each of these category area combinations is in the "market basket" consumed by different groups of people . Different published consumer price indices differ in the weights, including the target consumer group and how frequently the weights are updated . The weights for many indices are modified only in January of even - numbered years and are held constant for the next two years . However, weights for the chained CPI (C - CPI - U) are updated each month, so they more accurately track short term shifts in consumption patterns . </P>

Who calculates the consumer price index on a monthly basis in the usa