40 PUMS Home Page



The United States Bureau of the Census gathers a variety of useful information when it conducts the census. This information covers an array of topics pertaining to the lifestyles, incomes, jobs, and families of United States citizens. Small "samples" are extracted from the data and are collectively called the Public Use Microdata Samples (PUMS).

The PUMS are computer-accessible files that contain records for a sample of housing units, with information on the characteristics of the units and the people in them. Within the limits of the sample size and geographic detail, you can use the PUMS to complete several types of tabulations.

The 1940 data collection was assembled through a collaborative effort between the United States Bureau of the Census and the Center for Demography and Ecology of the University of Wisconsin. The 1940 Census Public Use Sample Project was supported by The National Science Foundation under Grant SES-7704135.

All data released by the U.S. Bureau of the Census are subject to strict confidentiality measures imposed by U.S. legislation (Title 13, U.S. Codes). The census data can be used for statistical purposes only. The PUMS records contain information on the characteristics of housing units and the people in them. The PUMS are extracted from the census data in a manner that avoids disclosure of information that can identify households or individuals. To protect the confidentiality of the respondents, any information that would identify a household or an individual is excluded.

Microdata records identify no geographic area with fewer than 100,000 inhabitants. Microdata samples include only a small fraction of the population, drastically limiting the chance that the record of a given individual is even contained in a PUMS file, much less identifiable.





Summary Tape Files (STF) are designed to provide statistics with greater subject detail for geographic areas than is feasible or desirable to provide in printed reports. The census data contained in printed reports are arranged in tables. Population and housing characteristics are presented for specified geographic areas; for example a table may represent the number of rented housing units in a census tract, the number of persons 65 years of age or older in a city, or the total population of a county. Census data at the small-area level, such as census tracts and smaller, will contain limited subject matter detail. STF files, in machine readable format, mimic this table layout.


For more information on the 1940 PUMS dataset, refer to the 1940 Census of Population and Housing Public Use Microdata Sample Technical Documentation. For a copy of the documentation, contact Data User Services Division, Systems and Programming Branch, Bureau of the Census, Washington, D.C. 20233. Telephone: (301) 763-4100.


For additional information concerning particular subject matter topics on the files, contact Population Division, (301) 763-7962, or Housing Division, (301) 763-2873, Bureau of the Census, Washington, D.C. 20233.



Census, United States, Demographics, Populations, Housing, PUMS.