How does IPUMS let you sort by county? To my knowledge PUMS does not have a county indicator.


README document for the PUMS specifically states that county and city are not indicated in the data. As far as I understand IPUMS is pulling data from PUMS, so how is it able to filter by county?

Sorry if this is a dumb question, I just started working with PUMS.



IPUMS creates several variables in addition to pulling data from the PUMS. When using IPUMS data, you’ll notice there are a number of variables created by IPUMS designed to assist researchers in their work. In particular, the COUNTY variable in IPUMS-USA is created by merging data from the PUMS (via the PUMA varaible for modern ACS samples) along with the ICPSR (Inter-University Consortium for Political and Social Research) coding scheme. This creation of the COUNTY variable is not perfect, and a number of counties are unable to be identified.