Unique identifier for secondary families?

Hello! I am conducting an analysis of secondary families using the CPS ASEC. In cases where there are more than one secondary family in a household, I need to distinguish between the two of them (or three or four). Is there a unique identifier for secondary families? Any suggested methods for creating one? Using a concatenate command and combing the serial and ftype only works if there is just one secondary family. Any suggestions?

Thanks!

The FTYPE variable in IPUMS-CPS, unfortunately, does not have a corresponding unit identification variable. This identification of secondary families is performed by the Census Bureau and released with the public use files. You could, in theory, combine FAMREL, and FTYPE to identify most secondary families, but as you have noticed this is not a perfect method. Since you are using the ASEC sample you could also use the FTOTVAL to group secondary families within households.

I hope this helps.