Code Lists, Definitions, and Accuracy

View the detailed codes and definitions for variables, statistical testing, and an explanation of sample design, methodology, and accuracy for the ACS.

User Notes

Learn more about issues impacting the American Community Survey, including design, collection, production, and data release.

Errata Notes

Learn more about errors and/or corrections related to the American Community Survey.

Data Suppression

Learn more about why certain American Community Survey estimates are not available due to data suppression.

Table & Geography Changes

Explanation of changes in the universe of geographic entities, changes to GEOID codes, and comparability changes.

Table Shells and Table List

View the layout of American Community Survey tables without the estimates or margins of error filled in.

PUMS Documentation

Learn more about how to work with the American Community Survey Public Use Microdata Sample (PUMS) files.