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 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.
The datafile is documented in a codebook containing a data dictionary and supporting appendix information. Information on data processing, accuracy of the data, and sample design is also included.
The PUMS from the 1990 Census contain individual- and household-level information from the "long-form" questionnaires distributed to a sample of the population enumerated in the Census. Each of the discrete PUMS files contains two types of records: "household" records and "person" records. Although the length of each of these record types is identical (231 charaters), the files are hierarchical in structure; each person record has a logical and physical relationship to the household record which precedes it.
Each household record is followed by a varying number of person records (one for each member of the household). Data items in this collection include the individual responses to the basic social, demographic, and economic questions asked of the population in the 1990 Census of Population and Housing.
Information from the census was derived either from questions asked of the entire population or from questions asked of only a sample of the population. Those questions asked about every person and housing unit are called 100-percent or short-form questions. The others are called sample or long-form questions.
Those households receiving the short-form questionnaires were asked only the 100-percent questions, and those receiving the long form were asked both the 100-percent questions and the sample questions. Sampling rates vary depending on geographic location and population size.
PUMS data contain a sample of the individual long-form census records showing most population and housing characteristics with identifying information removed.
For more information on the universe consult the PUMS home-page.
The coding system varies for each census, so it is important to have access to the codebook for each census in order to assess the meaning of a specific field in a census record and its comparability across censuses. Very little comparability exists between geographic identifiers on each of the previous files, but housing and population characteristics are similar.
The sample questionnaires were edited for completeness and consistency, and substitutions or allocations for any missing data were made. Allocation flags appear at the end of each record to indicate when an item has been allocated. A user wishing to tabulate only actually observed values can eliminate variables with allocated values.
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.