Is a crosswalk from County to PWPUMA possible?

I am trying to connect individuals in post-2012 IPUMS data to the county-based commuting zone in which they work using the PWPUMA variable. I poked around for a bit on the map of 2010 PWPUMA/MIGPUMAs (, and I could not find an instance in which a county crossed over PWPUMA boundaries. I know that PWPUMAs frequently contain several counties, but I first wanted to ask whether or not any counties cross over PWPUMA boundaries? That is, can each county be uniquely associated with a PWPUMA?

Second, while I understand that many PWPUMAs contain multiple counties and that individual level PUMS data cannot always identify a PWCOUNTY due to confidentiality, I wanted to ask if a crosswalk existed that maps counties into the PWPUMAs in which they reside. If this were the case, then it would at least be possible to map the place of work of a given individual in the ACS IPUMs samples to some set of counties. This would go a long way in identifying the commuting zone in which a person works, especially for larger commuting zones, without losing the person-level chacteristics of the PUMS data.

Thanks for all the help,
Robert McDonough

I’ll try to address your questions one at a time.

First, post-2012 PWPUMA boundaries (via PWPUMA00) are effectively tied to county boundaries (see this page for more details). This is why you do not find any cases where the boundaries cross. This detail is not the case for samples prior to 2012.

Second, Although there does not exist an existing crosswalk mapping PWPUMAs to identifiable counties, you can roughly approximate such a crosswalk. This crosswalk between 2010 PWPUMAs and 2010 PUMAs identifies which PUMAs correspond to specific PWPUMAs. Then, using the PUMA and COUNTYFIPS variables, you can see which PUMAs relate to a subset of identifiable counties. Since not all counties are identifiable, we do not make this specific crosswalk available but that does not mean that you cannot create it yourself.

Finally, since you sound interested in commuting zones, you may want to check out PWMET13.

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Thanks so much for the helpful information and links! The final PUMA criteria document was something for which I had been looking.

I do have a followup on the second point, though. As you suggest, for those PUMAs which relate to the subset of identifiable categories, it seems straightforward enough to connect a PWPUMA to a county. This is helpful, but not exactly what I want to do. Rather, I want to connect each PWPUMA with the set of counties it is composed of. That is, I want to use the PWPUMA variable to connect an individual with the set of counties in which they could possibly be working. I know that I cannot associate each individual with a unique county of work, but since PWPUMA boundaries are tied to county boundaries, it seems possible to at least connect each individual with the larger(contiguous) set of counties in which the work, as defined by PWPUMA.
Is this the case? If so, how might I go about finding which counties compose with PWPUMAs?

Thanks again

I looked around for something online that would make it easy to crosswalk from the 2010 Migration & PW PUMAs to counties–it definitely seems like something that should exist–but I came up empty. There are crosswalks from PWPUMA to PUMAs and from PUMAs to tracts, and you can use those to produce a county crosswalk, but I that’s not exactly “easy.”

Fortunately, when I was working on extending our migration and place-of-work geographic variables last year, I happened to create a county crosswalk! I’ve attached it here. I’ll also add an item to our work plans to add this to our geographic tools pages in the future. Feel free to reply if you have any questions or issues using this doc. ipums_migpwpuma10_county_crosswalk.csv (62.8 KB)

Notes: This file identifies counties by concatenating state and county FIPS, and MIG/PW PUMAs by concatenating state FIPS with PUMA code. The codes include leading zeros, which will be dropped if you open it in Excel or some other software packages.

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That’s awesome! Thanks so much for this.

By the way, is pointing out that this crosswalk should exist a mug-worthy contribution?

Sorry, Robert, we save the mugs for error reports. Even the very best feature requests shall remain mug-less.