Data tabulation issues are focused on those processes where the data collection ends. Data tabulations encompass all aspects of the Census Bureau involved with processing the basic record database. It also includes provisions made through the Census Bureau for the [prospective] external Census Bureau data user to tabulate data from the basic record database (a potentially new feature for Census 2000, not available previously). Products are those sets of tabulated data organized by the Census Bureau for public access and encompass the preplanned conventional printed reports, data files and Internet based cyber-products. Products also include important "by-products" from the decennial census such as the TIGER/Line files.
Decisions Regarding Adjustment
Census 2000 Adjusted Data -- Census 2000 Adjusted Data are available via http://www.sscnet.ucla.edu/issr/da/Adjusted/adjust_web.html. There is a summary of the background leading to the eventual availability of these data on that website. The Census Bureau has no plans to make these data available. Users of these data should note that both officially and statistically these data are neither "corrected" data nor "more accurate" data than the data released to the public by the Census Bureau. It can be misleading to suggest that these data are somehow better than the official Census 2000 data. These data were not used by the Census Bureau as it was concluded that there was insufficient evidence to conclusively determine that their usage could improve the summary data as initially tabulated.
Census released this information regarding the Census decision not to adjust the Census 2000 data: "After assessing considerable new evidence, the Executive Steering Committee for Accuracy and Coverage and Evaluation Policy (ESCAP) has recommended to me that unadjusted Census 2000 data also be used for nonredistricting purposes. The effect of this new evidence is that the Accuracy and Coverage Evaluation (A.C.E.) survey overstated the net undercount by at least 3 million people, The cause of this error was that the A.C.E. failed to measure a significant number of census erroneous enumerations, many of which were duplicates. This level of error in the A.C.E. measurement of net coverage is such that the A.C. E. results cannot be used in their current form. This finding of substantial error, in conjunction with remaining uncertainties, necessitates that revisions, based on additional review and analysis, be made to the A.C.E. estimates before any potential uses of these data can be considered.
"As a member of the ESCAP and as acting director of the Census Bureau, I concur with and approve the committee's recommendation that unadjusted data be used for nonredistricting purposes and have decided that the Census Bureau will release the remaining Census 2000 data products, postcensal estimates and survey controls using unadjusted data. It is reasonable to expect that further research and analysis could yield revised A.C.E. estimates and that these and that these revised estimates could be used to improve estimates developed as part of the Census Bureau's annual population adjustments for survey controls and for other purposes." The earlier decision to release unadjusted data is summarized below.
The Commerce Secretary ruled out adjusting Census 2000 for use in the redistricting. This decision was in accord with the recommendation of the Census Bureau that unadjusted census data be released as the Census Bureau's official redistricting data.
Demographic Data Products
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Detailed results of Census 2000 are contained in a series of five files that you can access through the Internet and on CD-ROM or DVD. Several related electronic and print products include Demographic Profiles of most geographic areas; Quick Tables that allow users to choose from among approximately 50 table shells, then specify the geographic area and the universe or population subgroup (such as the African American or the Hispanic population); and approximately 30 Geographic Comparison Tables that enable users to compare key data items across geographic areas. In addition, there are three series of reports available in print and in Portable Document Format (PDF) on the Internet.
First Data Released from Census 2000
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Census 2000 Public Law 94-171 Redistricting Summary File
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P.L. 94-171 Subject Matter Data. The first Census 2000 data files released contain data required for redistricting. The data include tabulations for the total population and the population 18 years old and over for 63 race categories, Hispanic or Latino, and race by not Hispanic or Latino. Detailed tabulations are presented data down to the census block level, and are/will be available through the Internet and through two CD-ROM series (state and national files). The PL-94-171 data file record layout is described in these files: http://www.census.gov/clo/www/plrecordnew.pdf and http://www.census.gov/prod/www/abs/pl94-171.pdf.
Overall Redistricting Program. The overall scope of the P.L. 94-171 data framed in the redistricting process, and more related detail, is available on the Census Bureau redistricting web site.
Census FTP Server. Connect with the Census 2000 FTP site, to download the P.L. 94-171 data, and to learn more about the file structures available via the FTP site. See related information about use of the FTP site elsewhere in this Web site and about processing the FTP downloaded data at this location on this Web site.
Census 2000 Summary File 1
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Summary File 1 (SF 1) presents counts and basic cross-tabulations of information collected from all people and housing units. This information includes age, sex, race, Hispanic or Latino origin, household relationship, and whether the residence is owned or rented. Data will be available down to the block level for many tabulations, but only to the census-tract level for others. Summaries are included for other geographic areas such as ZCTAs and Congressional Districts.
See Summary File 1 for more detailed information about content, structure, access to and use of Summary File 1 data.
Census 2000 Summary File 2
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Summary File 2 (SF 2) contains 100-percent (complete count) population and housing tabulations. For some types of subject matter (e.g., single year of age data) more detailed data are provided in Summary File 2 as compared to Summary File 1. Data are iterated for a selected set detailed race and Hispanic (Latino) origin groups, as well as American Indian and Alaska Native tribes. The lowest level of geographic tabulation is census tract. A population-size threshold must be met before data are provided for a particular group.
See Summary File 2 for more detailed information about content, structure, access to and use of Summary File 2 data.
Census 2000 Supplementary Survey Data
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National and state data are available from the Census Bureau's Census 2000 Supplementary Survey (C2SS). The 700,000 household survey was conducted in 1,203 counties simultaneously with last year's census and was designed to test the operational feasibility of collecting long form-type data independently of a decennial census. The survey uses the American Community Survey questionnaire and methodology and was an operational success.
Details concerning the scope and release of these data are located at the URL http://www.census.gov/Press-Release/www/2001/ntc072001.html.
The 107 core data tables and documentation may be accessed via the Census FTP server: http://ftp2.census.gov/census_2000/datasets/Census_2000_Supplementary_Survey/.
Census 2000 Summary File 3
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Summary File 3 (SF 3) contains population and housing tabulations based on the Census 2000 long-form questionnaire. These summary data are estimates of total universe values and are subject to sampling variability. The SF3 data are the most widely used set of machine-readable data released from the Census 2000 as the result of this set of "richer demographic" data being available down to the census block group (BG) level of geography. The BG summary level is the smallest geographic area for which sample-based data from Census 2000 are tabulated for public use.
See Summary File 3 for more detailed information about content, structure, access to and use of Summary File 3 data.
Census 2000 Summary File 4
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Summary File 4 (SF4) contains population and housing tabulations based on the Census 2000 long-form questionnaire. These summary data are estimates of total universe values and are subject to sampling variability.
The SF4 contain data similar to the SF3 ("PCT" and "HCT" tables) iterated for detailed race/ethnicity categories. Whereas SF3 provides data tabulated down to the block group level of geography, the low level geography for SF4 is census tract.
See Summary File 4 for more detailed information about content, structure, access to and use of Summary File 4 data.
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The Demographic Profiles provide key, most widely used, Census 2000 data for cities/places, counties, and larger geographic areas.
The Demographic Profiles are organized as follows:
DP-1 Profile of General Demographic Characteristics
DP-2 Profile of Selected Social Characteristics
DP-3 Profile of Selected Economic Characteristics
DP-4 Profile of Selected Housing Characteristics
Subject Matter. The Demographic Profile contains the 100-percent and sample data. 100-percent (complete count) include data on sex, age, race, Hispanic or Latino, household relationship, household type, group quarters population, housing occupancy, and housing tenure. Sample items include population data on school enrollment, educational attainment, marital status, grandparents, veteran status, disability status, residence, nativity and place of birth, foreign born, language spoken at home, ancestry, employment status, commuting to work, occupation, industry, class of worker, income, and poverty status. Sample items include housing data on units in structure, year structure built, rooms, year householder moved into unit, vehicles available, house heating fuel, occupants per room, value, mortgage status and monthly owner costs, and rent-related items.
Geography. The Demographic Profiles are available for the following types of geographic areas:
Nation, Region, Division
Metropolitan Area (whole and by state part)
American Indian Area/Alaska Native Area/Hawaiian Home Land (whole/state part)
County and County Subdivision
Alaska Native Regional Corporation
The Demographic Profile technical documentation (PDF) may be accessed at http://www.census.gov/prod/cen2000/doc/ProfileTD.pdf
Access the CSV structured data files at the URL: http://www2.census.gov/census_2000/datasets/demographic_profile/. See related information about converting the CSV formatted files to DBF using the Proximity Dataview software.
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Files described in this section are files that are generally not part of the pre-planned data file products, but are particularly important and/or contain highly in-demand data for certain user communities.
Journey to Work -- County-to-County Worker Flow Data/Analyses
The Journey to Work (County-to-County Worker Flow) data show where people worked and where they resided at the time of Census 2000. These data were tabulated from responses to long-form questions on where people worked, allow users to sort based on the county of residence or the county of work. These data files enable users to look at the number of people who work in a county and determine where they reside whether in an adjacent county or in another state.
Basic data are accessible via http://www.census.gov/population/www/cen2000/commuting.html. The files have been created in two formats Excel spreadsheet and ASCII (plain text). The Excel files and the uncompressed ASCII files may be viewed with browser software. The Excel files are accessible via word processing, spreadsheet or database programs. The ASCII files may be imported into various software applications.
Houston area regional focus
-- assessing geodemographics across a set of metropolitan areas
Proximity has developed wide-ranging, production datasets, featuring Census 2000-related geodemographic data resources for the Houston-Galveston-Brazoria CMSA (Consolidated Metropolitan Statistical Area). These data may be accessed at http://proximityone.com/48201.htm.
This same set of data resources is available for any area in the U.S.
Most of these data resources have been developed in the form of shapefiles where the corresponding dbase file is loaded with Census 2000 demographics. These files exist in a ready-to-map form, or the dbase files can be used in non-mapping applications as well.
Demographic data are provided by census block (a 38,000 census block demographic file), block group, census tract, and ZIP code tabulation area. Files also include specially aggregated data developed for school districts and traffic analysis zones.
Proximity has developed this set of data resources partly to demonstrate the nature and scope of Proximity data resources available for the U.S. In addition, Proximity seeks to make these data available for immediate use to meet Houston area public sector planning and analysis needs.
ZIP Code Tabulation Area Demographic Data A U.S. by 5-digit ZIP Code Tabulation Area (ZCTA) demographic data file is available via downloading from Proximity. Additional information on the structure, content, and access to the ZCTA demographic data file is available at http://proximityone.com/zctadata.htm.
State by Census Tract Demographic Profile Files Statewide Census 2000 census tract demographic profile files ("DP2000E") may be downloaded at http://proximityone.com/dp2000e.htm. These demographic profile files have been developed by Proximity using the Census Data Integrator (CDI) software with source data from Summary File 1. Users of the CDI software may develop similar profile databases for any type of summary level (e.g., counties, zip code tabulation areas, places, etc.).
U.S. by County Summary File The U.S. by County Summary file contains Census 2000 total population for all 3,141 counties. See the Largest 100 U.S. Counties based on Census 2000 web page/table ( http://www.proximityone.com/cty100.htm) that is based on use of this file for more information.
U.S. by City/Place Census 2000 Population, Name, Codes Summary File Registered users may download this zip file that expands to an Excel 2000 spreadsheet file containing a record/row for each of the Census 2000 25,152 cities/places. Fields include state and place code, place name and total population. There is no fee for this file and there are no restrictions on use of the file. Most registered users may use existing userid and password to access this file. To register, complete the registration webform and check the checkbox for the Census 2000 Places Spreadsheet File.
U.S. by City/Place 1990 Census to Census 2000 Population and Population Change Summary File The U.S. by City/Place Summary file contains Census 2000 total population and 1990 Census to Census 2000 population change for all Census 2000 25,152 cities/places. See the Largest 100 U.S. Cities/Places based on Census 2000 web page/table ( http://www.proximityone.com/plc100.htm) that is based on use of this file for more information.
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Decennial Census Microdata Files. For decennial censuses, the term "microdata file" refers to a file that contains a sample of respondent data records. The preplanned decennial census microdata files referred to as the Public Use Microdata Sample (PUMS) files.
Census 2000 1% PUMS state files. The first Census 2000 Public one percent Use Microdata Sample (PUMS) files may be accessed via http://www2.census.gov/census_2000/datasets/PUMS/OnePercent .
Census 2000 5% PUMS state files. The Census 2000 five percent Public Use Microdata Sample (PUMS) files may be accessed via http://www2.census.gov/census_2000/datasets/PUMS/FivePercent/ .
See the Census 2000 PUMS Web page for more detailed information.
Other Microdata Files. In the case of the decennial census the PUMS files are preplanned sample files -- they contain a sample of respondent data records. Many other microdata files exist, corresponding to other statistical programs.
An important set of microdata files are derived from Current Population Survey. See link below. There are a continuing set of topical, monthly, national scope surveys with the March Supplement survey being of most general interest. A series of population profiles based on the CPS and related files is summarized at http://www.census.gov/population/www/pop-profile/profile2000.html.
The Federal Electronic Research and Review Extraction Tool or FERRET, http://ferret.bls.census.gov/cgi-bin/ferret, is a computer search tool developed by the Census Bureau and Bureau of Labor Statistics. FERRET enables the user to download sections of selected microdata files and/or develop cross-tabulations, real-time, via the Internet. FERRET is designed for a wide range of users including statisticians, researchers, policy-makers and analysts in general. Does not support decennial census PUMS tabulations.
Proximity Geodemographics WebCourse
-- using microdata files (Module 1, Section 11)
Microdata File Features (Minnesota IPUMS)
Census 2000 Public Use Microdata Sample Files (Census Website)
1990 Census PUMS Documentation (Univ. Michigan)
Download 1990 Census and earlier PUMS Files (Minnesota IPUMS)
Download 1990 Census PUMS Files (Census DES Website)
Census Bureau PUMS Product Support Page
Download 1990 Census PUMA Shapefiles (Census Website)
Decennial Census Related Microdata Files
Current Population Survey Microdata Files (Annual Demographic File)
American Community Survey Microdata Files (Census Website)
PUMS and Federal Agencies
Tabulation Option References
University of Virginia Geospatial and Statistical Data Center
1990 Census PUMS Crosstab Web-Interactive Facility
CPS and Related Microdata Files Accessible via FERRET
-- Crosstab Web-Interactive Facility (no PUMS)
Census 2000 Public Use Microdata Sample (PUMS) Files Recap: Two PUMS files are planned for release: 1-percent and a 5-percent sample.
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Three series of printed reports will be prepared with one report per state and a national summary volume.
Summary Population and Housing Characteristics (PHC-1)
This series, containing information collected on a 100-percent basis, present information for states, counties, places, and other areas. Comparable to the 1990 CPH-1 report, Summary Population and Housing Characteristics, it will also be available on the Internet.
Summary Social, Economic, and Housing Characteristics (PHC-2)
This publication includes information on the sample population and housing subjects for the same geographic areas and information and will be comparable to the 1990 CPH-5 census report series, Summary Social, Economic, and Housing Characteristics (1990 CPH-5). It will also be available on the Internet.
Population and Housing Unit Totals (PHC-3)
This publication includes population and housing unit totals for Census 2000 as well as the 1990 and 1980 censuses. Information on area measurements and population density will be included. This series will include one printed report for each state plus national report; it will also be available on the Internet.
School District Data
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For Census 2000 data tabulations, school district boundaries are defined as they existed for the 1999-2000 school year. School district codes are coded in the Census Bureau TIGER files.
There are no summary statistic data for school districts in the regular preplanned data products from Census 2000. Present plans call for a few data products to be produced by the Census Bureau, under sponsorship of the U.S. National Center for Education Statistics (NCES), as well as the School District Special Tabulations (SDST). The subject matter covered in the SDST is expected to be similar to that produced from the 1990 Census.
The first school district data are produced are school district summaries derived by aggregating the P.L. 94-171 census block level data. Unlike the 1990 Census, school district boundaries for Census 2000 coincide with census block boundaries. As a result, it is possible to aggregate data for census blocks to school district areas.
All summary statistics derived from a process of aggregating census blocks to school district
areas are characteristics of the total population or housing (as further defined
by tabulation universes).