Monetary Adjustment Feature

The Consumer Price Index (CPI) is a measure produced by the Bureau of Labor Statistics to indicate the relative price of a set of goods and services across time in the United States. The CPI for all urban consumers (CPI-U) is the most widely used of price indexes. It is computed monthly based on expenditure patterns and annual average indexes represent the average over the 12 months of the calendar year. The CPI-U and additional information about consumer price indexes are available on the U.S. Bureau of Labor Statistics website.

IPUMS has selected the CPI-U as the default price index because of its widespread use and availability across a long time span. The CPI-U is available back to 1947 in its seasonally adjusted form. For the 1921 to 1946 period, a national index is available but it is not seasonally adjusted. An index was estimated by the Bureau of Labor Statistics for the 1913 to 1920 period. Samuel H. Williamson of Measuring Worth has compiled a series back to 1774 which enables us to extend the CPI-U series back to 1850, the first year for which we have census microdata in IPUMS USA. These data are available on the Measuring Worth website.

Missing data codes
In the adjusted version of a variable, the adjustment factor is only applied to codes that represent monetary values in the original variable, including top and bottom codes. Missing data codes (NIU, Refused, Don't Know, and No response) from the original variable are compressed into a single code consisting entirely of 9s in the adjusted version of the variable. This single missing data code is two digits wider than the missing codes in the original variable; the code is analogous to NIU for the adjusted variable.