# Help with linking PUMAs to counties **URL:** \ **Category:** USA\ **Created:** [May 3, 2023, 3:25pm UTC](https://forum.ipums.org/t/help-with-linking-pumas-to-counties/5263 "2023-05-03T15:25:16Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![Sampriti\_Sarkar](https://avatars.discourse-cdn.com/v4/letter/s/77aa72/32.png) [@Sampriti\_Sarkar](https://forum.ipums.org/u/Sampriti_Sarkar)\ **Post date:** [May 3, 2023, 3:25pm UTC](https://forum.ipums.org/t/help-with-linking-pumas-to-counties/5263/1 "2023-05-03T15:25:16Z")
Hello! I am a graduate student using IPUMS for the first time and it would be great if someone can help me. I am doing a repeated cross-section analysis. From what I read, I gathered that PUMAs are not comparable over time as the boundaries change over time. However, I am using data from 2012 to 2019 (1% ACS), which is using similar boundaries (2010). So, my first question is, if I use data from 2012 to 2019, can the PUMAs be compared over time? The second thing I am struggling with is matching the PUMAs to counties. I have some data in county level, and it would be really great if I can match the counties with PUMAs. Can anyone help me with the steps to do this? or guide me to resources that can do this? that would be really helpful for me. Thank you so much! ---
**Author:** ![Chris\_B](https://avatars.discourse-cdn.com/v4/letter/c/43a26b/32.png) [@Chris\_B](https://forum.ipums.org/u/Chris_B)\ **Post date:** [May 3, 2023, 5:26pm UTC](https://forum.ipums.org/t/help-with-linking-pumas-to-counties/5263/2 "2023-05-03T17:26:34Z")
For your first question, I am not aware of any changes to the PUMA definitions since 2010 so I don’t see why using '12-'19 PUMA data would cause any issues. Sadly there is no straighforward way to accomplish your second ask around a 1:1 crosswalk of PUMAs to counties. Some counties are in multiple PUMAs and vice-versa. You’d need to do some kind of probabilistic match, which may be difficult if it’s not been done already. See this helpful answer from an IPUMS Staff member: [Crosswalk County FIPS to PUMA/MIGPUMA from 2005-2019 - #2 by JonathanSchroeder](https://forum.ipums.org/t/crosswalk-county-fips-to-puma-migpuma-from-2005-2019/4413/2) “Some counties correspond to multiple PUMAs, and vice versa, so it’s not possible to allocate data _directly_ from one to the other.” ---
**Author:** ![Sampriti\_Sarkar](https://avatars.discourse-cdn.com/v4/letter/s/77aa72/32.png) [@Sampriti\_Sarkar](https://forum.ipums.org/u/Sampriti_Sarkar)\ **Post date:** [May 4, 2023, 3:49am UTC](https://forum.ipums.org/t/help-with-linking-pumas-to-counties/5263/3 "2023-05-04T03:49:04Z")
Thank you for your helpful response!