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How Do I Select PUMAs on the Microdata Access Tool (MDAT) for ACS 5-Year Estimates with Dual Vintage PUMAs?

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How Do I Select PUMAs on the Microdata Access Tool (MDAT) for ACS 5-Year Estimates with Dual Vintage PUMAs?

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:

  • 2022 records are provided using 2020 PUMA vintage 
  • 2021, 2020, 2019, and 2018 records are provided using the 2010 PUMA vintage 

 

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?

  • 2022 vintage of the ACS 5-Year PUMS (as well as future releases of 2023, 2024, 2025 ACS 5-Year PUMS
  • 2015, 2014, 2013, 2012 vintages of the ACS 5-Year PUMS.


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:  

  • Create one MDAT table using the PUMA10 variable
  • Create a separate MDAT table using the PUMA20 variable
  • Add data together to get the overall estimate, taking into account geography changes between the vintage.

 

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

  • Visit the Microdata Access Tool at data.census.gov/app/mdat/
  • Select Dataset: Choose ACS 5-Year Estimates Public Use Microdata Sample
  • Select Vintage: Choose 2022
  • Click the Next button
  • Using the Select Variables tab
    • Type PUMA in the label box
    • Click the check boxes to select PUMA10
    • Select any other variables for your table, as desired
  • Click the Select Geographies tab
    • Click State
      • Choose the desired state(s) (e.g. Louisiana)
  • Click the Data Cart Tab
    • Click PUMA10
    • Uncheck the box that says "include in universe"
  • Type 02201 in the value box and mark the check box. This corresponds to the 5-digit PUMA code for Regional Planning Commission 2 in St Tammany Parish, LA in the 2010 vintage of PUMAs.
  • View results based on the portion of records containing 2010 PUMA codes

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

  • Visit the Microdata Access Tool at data.census.gov/mdat
  • Select Dataset: Choose ACS 5-Year Estimates Public Use Microdata Sample
  • Select Vintage: Choose 2022
  • Click the Next button
  • Using the Select Variables tab
    • Type PUMA in the label box
    • Click the check boxes to select PUMA20
    • Select any other variables for your table, as desired
  • Click the Select Geographies tab
    • Click State
      • Choose the desired state(s) (e.g. Louisiana)
  • Click the Data Cart Tab
    • Click PUMA20
      • Uncheck the box that says "include in universe"
  • Type 02202 in the value box and mark the check box. This corresponds to the 5-digit PUMA code for Regional Planning Commission 2 in St Tammany Parish, LA in the 2020 vintage of PUMAs.
    *As demonstrated in this example, 5-digit PUMA codes may change over time. See the “Notes” section below for more details on this.
  • View results based on the portion of records containing 2020 PUMA codes

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:

  • PUMA boundaries and/or codes may change substantially between vintages, requiring analysis to determine which PUMA codes to use for. In the above example, the PUMA code for Regional Planning Commission 2 in St Tammany Parish changed across years. In 2010, the PUMA code is 02201 and in 2020 it is 02202.
  • The MABLE/Geocorr tool is helpful to identify changes in PUMAs between vintages. The tool allows you to calculate the proportion of a
    PUMA code from the 2010 vintage that lies within the new PUMA codes from the 2020 vintage. It also provides you with an allocation factor so that you may crosswalk old PUMA codes to new PUMA codes. Check out this short video to learn more about how to use the MABLE/Geocorr tool to crosswalk geographies.
  • Page 13 of ACS 5-Year PUMS User Guide contains more information about dual vintage PUMAs and resources to make sense of PUMA changes over time.

Contact Us

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.

Page Last Revised - January 22, 2025
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