SHADAC Expertise

ACS Microdata

ACS microdata are available for download to conduct your own analyses. Microdata are the original data records for each observation, although de-identified according to strict Census Bureau procedures. These data files tend to be very large, in raw format (usually ASCII flat file), and require analytic software to process files.

Federal data sources are usually available ready to load into SAS, Stata or SPSS.  If you use something else, convert it with StatTransfer software (available through Stata).

Where to download microdata:

Microdata are available directly through the Census Bureau or from a few third party data access sites.  These are public use microdata samples (PUMS), which include a sample of the full ACS file (about 67% of records).  The full fill is not publicly available, but can be accessed through a research data center.

SHADAC recommends accessing public use microdata from the Integrated Public Use Microdata Series (IPUMS).  IPUMS offers:

  • Harmonized variable names and labels over time, allowing for easier trend analyses.
  • The site is free and easy to use.
  • Users can download only what variables are needed, which can be a big time saver.
  • IPUMS is the only microdata source for 2008 ACS data with logical edits applied.  See SHADAC's technical brief for information on these edits, "A Summary of the American Community Survey Logical Edits Applied to Health Insurance Coverage."
  • IPUMS typically Has ACS public use microdata ready within a week of the Census Bureau release.

Data files can also be downloaded directly from these Census Bureau sites: