I was trying to use the county code from CPS data, and found two questions.
Based on the whole CPS data I downloaded from the IPUMS webstie, there are about 280 counties that have county code, i.e. could be identified, after year 2008, however, based on the information provided here: https://cps.ipums.org/cps/codes/count…, there should be about 549 counties that could be identified after 2005. I do not know why I could only identify 280 counties from the original data. I checked some cases, like county code== 6013, which should be identified based on the above list, but I could not find the county code.
For the counties that could be identified, I was wondering if this kind of case exists in the CPS that within the same county, some observations miss county codes while another observations do not. Because I need to aggegate the CPS to the county level and I was worried about the selection biased. If there is no selection in the counties that could be identified, i.e. all the observations in that county have the county code, then the aggregation process should be fine, otherwise, it might have a problem.
Thank you in advance.