In some data years, public use microdata areas (PUMAs) do not appear as a selectable geography on the Microdata Access Tool (MDAT). This situation occurs when the ACS 5-Year Public Use Microdata Sample (PUMS) files contain dual vintage PUMAs.
Why Do Some Datasets Have Dual Vintage PUMAs?
To understand dual-vintage PUMAs in a single PUMS file, consider the 2022 ACS 5-Year PUMS file. The file is made up of all the records from each of the ACS 1-Year PUMS files: 2022, 2021, 2020, 2019, and 2018. Each record on the PUMS files will contain either the PUMA10 or PUMA20 code, based on which year the record’s data were collected.
In the 2022 ACS 5-year PUMS file:
Due to disclosure concerns, it is not possible for the Census Bureau to update the PUMA codes for the records from 2021 and earlier to 2020-based PUMAs by using their detailed geographic locations.
Which ACS 5-Year Datasets Have Dual Vintage PUMAs in the Microdata Access Tool?
How Do I Access Data for Dual Vintage PUMAs using the Microdata Access Tool:
Example: Accessing total population for Regional Planning Commission 2 in St Tammany Parish, LA from the 2022 ACS 5-Year PUMS
The process to get a create a custom table for ACS 5-year PUMS with dual vintage PUMAs on the Microdata Access Tool includes a minimum of 3 steps:
Please be aware that the process to create custom tables on MDAT for ACS 5-year PUMS with dual vintage PUMAs data is difficult. The steps below cover the process to get data for a single PUMA in these datasets. If you need data for multiple PUMAs, you may want to consider other alternatives such as (1) Using ACS 1-year PUMS instead of ACS 5-year PUMS; (2) Using vintages of the ACS 5-year PUMS that do not contain dual-vintage PUMAs, such as the 2021 ACS 5-year PUMS; or (3) Downloading microdata from the ACS FTP site to create custom tables using your own statistical software instead of using MDAT.
Example: Accessing total population for Regional Planning Commission 2 in St Tammany Parish, LA from the 2022 ACS 5-Year PUMS
Step 1: Create a table using the 2010 PUMA vintage
Step 2: Create a table using the 2020 PUMA vintage, following similar steps but using the PUMA20 variable and correct corresponding code for your desired PUMAs
Step 3: Add the numbers from the 2010 and 2020 tables together
The last step is to add the data from the two tables together. In this example, the estimated total population for Regional Planning Commission 2 in St Tammany Parish, LA based on the 2022 ACS 5-Year Public Use Microdata Sample is:
Total population = 98,173 + 22,820 = 120,993
Notes:
Email us at census.data@census.gov for any questions or comments you may have. For more guidance on data availability and using data.census.gov, the Census API, and Microdata Access, visit our Resources page.