Investigator(s): U.S. Bureau of the Census, and Inter-university Consortium for Political and Social Research
In addition to the historic Census files, 1790-1950, ICPSR archives and distributes Census data acquired from the United States Census Bureau as well as files prepared by ICPSR and other principal investigators for the decennial years 1960, 1970, 1980, 1990, and 2000. These include major sets such as the Summary Tape/Count Files, Master Enumeration District List (MEDList) files, and Public Use Microdata Samples (PUMS), as well as various subsets. For the 2000 Census of Population and Housing, and with funding from the National Science Foundation and the National Institutes of Health, ICPSR distributes files from the following Census components: P.L. 94-171 Redistricting Files, Summary File 1 - Advanced National, Final National, and States, Summary File 2 - Advanced National and States, Summary File 3 - States and National. In addition, ICPSR has created subsets from Summary File 1, Advanced National, and Summary File 1, States, in order to facilitate analyses of the data. Each subset comprises all of the cases in one of seven census summary levels: the nation, states, counties, places, five-digit ZIP code tabulation areas, whole census tracts, and census tracts in places. Summary Files 1 and 2 (SF 1 and SF 2) contain the 100-percent data, which is the information compiled from the questions asked of all people and about every housing unit. They include population and housing characteristics. Selected aggregates and medians are also provided. SF 1 and SF 2 National files provide summaries for the entire United States, as well as for regions, divisions, states, counties, county subdivisions, places, American Indian and Alaska Native areas, tribal subdivisions, and metropolitan areas. The final national file includes data for urban (urbanized areas and urban clusters) and rural areas. Summary File 3 (SF 3) contains the sample data, which is the information compiled from the questions asked of a sample of all people and housing units. Summary files are released as individual files for each of the 50 states, the District of Columbia, Puerto Rico, and the United States. The 2000 Census Tract Relationship Files (CTRF) assist users in determining the relationship between 1990 and 2000 census tracts. They consist of four sets of files. Public Law (P.L.) 94-171 data provide states with data for voting districts (e.g., election precincts, city wards) in addition to standard census geographic areas such as counties, cities, census tracts, and blocks, in accordance with the requirement of the 1975 Public Law 94-171 which mandates the Census Bureau to provide redistricting data in a format requested by state governments. The 1998 Dress Rehearsal, P.L. 94-171, was conducted as a prelude to the United States Census of Population and Housing, 2000, in selected locations. The Profiles of General Demographic Characteristics contain the 100-percent data, which is the information compiled from questions asked of all people and about every housing unit. ICPSR has an agreement with the Census Bureau to distribute all of Census 2000 data plus the maps.