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Census Data Resources: American Community Survey

Subject Guide for Census Data Resources

Subjects Included in the ACS

  • Code Lists & Subject Definitions
    While many subjects are collected year after year, new subjects are added at various times. Use the year tabs on this page to identify subjects for a given year.

ACS Data Tools

  • Social Explorer
    **Limited to UGA affiliated users** - provides access to historical and current data.
  • Summary File (flat file) Download page
    ALL variables for ALL geographies; requires the use of statistical software to subset.
  • Summary File Retrieval Tool
    Easy-to-use Excel macro for downloading up to 20 tables of tract and Census block group data--see link under the heading, "Tools for using the ACS Summary File," to download a zipped (compressed) file.
  • Questionnaire Archive
    Seeing how a question was asked may help you understand the resulting data.
  • Glossary

Introduction to the American Community Survey (2005 to now)

The American Community Survey was created to gather detailed trend data for planning purposes on a more frequent basis than the decennial censuses. It is run every year and uses a quite different methodology from the decennial census long form. For this reason, while the subjects included in the ACS are very similar to the decennial long form subjects, data from the two surveys are often not directly comparable. Subjects are quite varied and include data on income, education (enrollment and attainment), employment and occupation, transportation to work, health insurance coverage, detailed housing characteristics like prevalence of complete kitchen and bathroom facilities and heating fuel, and more. Subjects are subject to revision (health insurance coverage was added to the 2009 questionnaire); check the technical documentation for specific subjects.

The ACS began full implementation in 2005 but group quarters were not included until 2006. The questionnaire is administered every month and the overall sample is accumulated over multiple years: geographies with more than 65,000 people are represented in the one-year (annual) data; geographies with between 20,000 and 65,000 people are represented in the three-year data; geographies with fewer than 20,000 people are represented in the five-year data. Data in the ACS, like the decennial long form, are available down to the Census block group level but estimates at this level may not be reliable given the smaller sample size of the ACS (12.5% before 2011; about 13.5% after 2011). Users should pay close attention to the Margins of Error published with the data—they can be quite large for small groups of population and small geographies.

Census Geography

ACS Documentation

  • By Year
    General technical documentation. Also, some ACS tables are suppressed for the smallest geographies; look for an appendix listing detailed tables for the 5-year estimates to find which are and are not available at the block group level.
  • Compass Data User Guides
    In-depth guides with information about interpreting margins of error and more. Often specialized for particular users, like for Researchers or for Users of Data for Rural Areas.
  • Summary of Questionnaire Changes
    Documentation that traces question changes from year to year.

Your Librarian

Sheila Devaney's picture
Sheila Devaney
Research & Instruction Department
Main Library
University of Georgia
912-268-0539 (For Spring 2021 please use my Google Voice number)