There is not a specific variable in the Food Security Supplement that gives the supplement respondent’s line number. There is a household-level variable that is currently not available through IPUMS CPS that gives the line number (LINENO) of the “current respondent” (CPS variable name hurespli in the original codebook), however, the questionnaire gives the instructions:
> “[Lead for two or more person households] This month we are asking some questions about food used in your household and the ways you are managing to meet your food needs.
> (The best person to answer would be the adult most knowledgeable about food shopping and meal preparation. Would that be you or someone else?) [Change respondent if needed and available, otherwise continue with current respondent]”
So it may not be the case that the Food Security questions where answered by the same person identified by hurespli. Other supplements do have variables specifically identifying supplement respondents (such as VETRESP for the Veteran Supplement), which leads me to further believe that the hurespli can not be depended on to identify Food Security Supplement respondents.
You can merge the hurespli variable from the NBER CPS supplement files onto your IPUMS CPS extract by following these details.The first is that NBER data includes non-response CPS households. So, if you drop the non-interviewed households from the NBER file, the record counts should align with IPUMS CPS record counts. Second, you should be able to perform a perfect 1:1 merge using HRHHID, HRHHID2, and LINENOas linking keys. Note that in the NBER file, you’ll need to rename the PULINENO to LINENO to allow the 1:1 merge to work properly.
I would also recommend contacting the Census Bureau directly to ask about whether or not it is possible to identify Food Security Supplement respondents if it is important to your research.
I hope this helps!