Technical documentation for counties not included in CPS public-use files

Hi,

I’m having trouble finding technical documentation that states the rules that are used to decide whether (or not) a county is included in the CPS public-use files. I know that the decision is primarily centered upon population size, but I’m trying to figure out whether there is a specific population size threshold that is used to make that decision, or if there are any other thresholds that are used to make the decision about which counties to identify in the public-use files.

Many thanks!

Although I am not able to find documentation of the exact decision rule, I can say that the identification of counties is constrained by respondent confidentiality. So, restricted counties will tend to be counties that have a population that is too small and would therefore risk the identification of individuals in the microdata. Looking at the 2018 ASEC sample, I do not see a county identified with less than 100,000 inhabitants.