Hello Glenn Rice,
Probably asking an obvious question but created an output with Geocorr2022 to get population allocation factors between zip codes and upper- and lower-chamber state legislative districts. I noticed I got 3 rows with blank ZCTA values but with a state legislative district (lower) 2020 assigned (see snapshot). These blanks were not present in the Geocorr2018 version.
Any insights or documentation I can read about these cases? Since they are a very very very small number, I'm thinking of dropping it but wanted to get a better understanding if there was a reason for them to exist.
Blanks in any Geocorr output indicate the absence of the source or target geography. In your example, 3, 9, and 2 are the number of persons in districts 101, 103, and 105 respectively that are not in any ZCTA.
For geo types without 100% coverage, Geocorr should show something like "[not in a place]" for the area name and "99999" for the code if the area is missing. I can add that to ZCTAs as well.
You can email me direct with questions about Geocorr. firstname.lastname@example.org