What is IPUMS-CPS?
IPUMS-CPS is an integrated set of data from over 50 years of the March Current Population Survey (CPS). Additionally, IPUMS-CPS include data from the many Basic Monthly samples. The CPS is a monthly U.S. household survey conducted jointly by the U.S. Census Bureau and the Bureau of Labor Statistics. Initiated in the 1940s in the wake of the Great Depression, the survey was designed to measure unemployment. A battery of labor force and demographic questions, known as the “basic monthly survey,” is asked every month. Over time, supplemental inquiries on special topics have been added for particular months. Among these supplemental surveys, the March Annual Demographic File and Income Supplement (hereafter referred to as the March CPS) is the most widely used by social scientists and policymakers.
To make cross-time comparisons using the March CPS data more feasible, variables in IPUMS-CPS are coded identically or “harmonized” across time. This harmonized dataset is also compatible with the data from the U.S. decennial censuses that are part of the Integrated Public Use Microdata Series (IPUMS-USA). Researchers can take advantage of the relatively large sample size of IPUMS-USA at ten-year intervals and fill in information for the intervening years using IPUMS-CPS.
IPUMS is not a collection of compiled statistics; it is composed of microdata. Each record is a person, with all characteristics numerically coded. In most samples persons are organized into households, making it possible to study the characteristics of people in the context of their families or other co-residents. Because the data are individuals and not tables, researchers must use a statistical package to analyze the millions of records in the database. A data extraction system enables users to select only the samples and variables they require.