Dear Glenn,
I have a relationship file/crosswalk file from GEOCORR. I mapped 2012 PUMAs (current geography for PUMAS/2021 PUMS) to 2020 Tracts (currently used for 2017-2021 ACS 5 year tables). I get quite a lot of duplicate County/Tract combinations. Does this mean that a 2020 tract appears in multiple 2012 PUMAs ? Here are some examples for VA (FIPS 51).
State Puma County Tract
687 51 51089 003 011302
737 51 51090 003 011302
688 51 51089 003 011303
738 51 51090 003 011303
442 51 51045 005 080100
509 51 51080 005 080100
445 51 51045 005 080301
510 51 51080 005 080301
511 51 51080 009 010100
756 51 51095 009 010100
>
Any help appreciated.
Dave