90 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 1990 PUMS contain individual- and household-level information from the long form questionnaires distributed to a sample of the population enumerated in the census.

The PUMS are available in samples that represent:

5% of the Population and Housing of the U.S.
which identifies all States and various subdivisions within them, including most counties with 100,000 or more inhabitants.

1% of the Population and Housing of the U.S.
which identifies all metropolitan territory and most M.A.s with 100,000 or more inhabitants individually, and groups of M.A.s elsewhere.

Selected group quarters are also included. The file contains individual weights for each person and housing unit. When applied to the individual records, the weights expand the sample to the total population. Both the 5% and 1% samples have the same subject content and vary only in geographic composition of the Public Use Microdata Area (PUMA). Each dataset is a subsample of the full census sample (approximately 15.9% of all household units) that received census long-form questionnaires.

The 1990 data collection were prepared by the United States Bureau of the Census. 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.

For more information on 1% vs 5% sample files consult the PUMS home-page.





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 1990 PUMS dataset, refer to the 1990 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.