Census Bureau

1990 CENSUS OF POPULATION AND HOUSING. PUBLIC USE MICRODATA SAMPLES (PUMS)  5% AND 1%

Availability:  PUMS 5% files are available on 7 CD-ROMS; PUMS 1% files are available as a 2 disc set. Individual files may be purchased  PUMS 5% also known as PUMS A; PUMS 1% as PUMS B See below for product id and pricing information.

Subject content: Individual records of responses to questionnaires with unique identifiers (names, addresses, etc.) removed so the confidentiality of respondents is protected. These files enable users to produce their own tabulations within the limits of the data provided.

Geography: Available for United States and outlying areas that meet a 100,000 minimum-population threshold. Currently, the standard PUMS products are the 5 percent and 1 percent samples for the United States and Puerto Rico, and a special 3 percent sample (not available on CD-ROM) dealing specifically with the elderly population. The 5 percent and 1 percent samples are similar in content to the "A" and "B" files made available in 1980. Besides the obvious difference in file size, the 5 percent and 1 percent files differ in the geography around which the files are constructed. For example, the Public Use Microdata Area (PUMA) is the lowest level of geography identified on any PUMS file.

The 5 percent sample is basically a county level file; that is the PUMA can be a single county (or county equivalent), a group of counties, a place, or county/place parts if that county had more than 200,000 persons. On the other hand, the 1 percent sample is basically a metropolitan area file. For this, the PUMA will be an MSA, groups of MSAs, parts of MSAs when the MA is larger than 200,000 persons, and groups of nonmetropolitan areas.

File format: flat ASCII, except that each record will be terminated with carriage return and linefeed characters. File structure: hierarchical. While no "value-added" user software is provided, the technical documentation includes a section with suggestions on how to use the files. All PUMS files have two record types: one for housing units, and one for persons. The number of records per file is determined by the sample size.

Census contact: Customer Services (orders), 301-763-INFO (4636)

Order Information

PUMS 5% CD-ROMs


All States CK-D90-PUM5-03-US1   $195 CSC

PUMS 1% CD-ROMS


All States CK-D90-PUM1-03-US1 $75 CSC