PUMS Documentation

View the available subjects, detailed codes for variables, changes related to each release, an explanation of sample design, methodology, and accuracy, and files to determine if you are using weights correctly for the American Community Survey Public Use Microdata Sample (PUMS) files. These documents are organized by data year.

Supporting data for the documentation below is available on the Accessing PUMS Data page.

2024

PUMS User Guide

Guidance for novice ACS PUMS files users.

2024 ACS 1-year PUMS User Guide [<1.0 MB]

PUMS Variable Changes and Explanations

Important information about 2024 geography and variable changes.

2024 ACS 1-year PUMS Variable Changes and Explanations [<1.0 MB]

Subjects in the PUMS

A list of topics included in each of the housing and population record files.

2024 ACS 1-year PUMS Subjects [<1.0 MB]

PUMS Code Lists

Detailed codes for variables that contain a large number of coded responses, such as ancestry and occupation.

2024 ACS 1-year PUMS Code Lists [<1.0 MB]

Data Dictionaries for PUMS Files

Includes variables available for each release of PUMS files on the Census Bureau FTP site, and how each variable is coded.

Microdata API Data Dictionaries

Includes variables available on the Microdata API, including microdata access on data.census.gov (MDAT).

Accuracy of the PUMS

A basic explanation of the sample design, estimation methodology, and accuracy of the data.

Note: 2024 is the final year ACS PUMS design factors will be published.

PUMS Top Coded and Bottom Coded Values

List of variables with responses exceeding a state-specific value that are replaced with a predetermined value.

PUMS Estimates for User Verification

Note that some of these estimates may be different from the estimates for the same characteristics published in data.census.gov. For an explanation of these differences, see the Accuracy of the PUMS above.