Can one compare 1990 pumas with 2000 pumas?
IPUMS USA hasn’t produced a 1990-2000 PUMA crosswalk, and we don’t currently have plans to do that. We provide some resources through the IPUMS USA Geographic Tools and Resources that can help with comparisons.
First, you could use our GIS boundary files to map 1990 and 2000 PUMAs and view their relationships. You could also perform a spatial intersection operation to determine the areas involved in boundary changes. This would require GIS software or a spatial analysis package for a statistical programming environment. You could also overlay these boundaries with block shapefiles from IPUMS NHGIS to identify which blocks are involved in boundary changes, and join to block-level population tables from NHGIS to determine the populations involved in those changes.
Or, if you wanted to avoid using GIS files, you could use the composition files for 1990 PUMAs and 2000 PUMAs to identify the components of these areas. Then you could associate those components with census blocks using NHGIS block-level data tables and determine associations across time using block-level geographic crosswalks from NHGIS.
We would eventually like to do similar work to associate 1990 PUMAs with later areas in order to extend more of our geographic variables back to 1990 samples (e.g., MET2013 and MET2023), but we have no timeline set for that work.