I noticed while using IPUMS that you only provide the NICs at the 3 digit level (although the original sample surveys go up to 5 since 1999). Hence, I tried to merge the orginal NSS data I have from my university with 5 digit industrial codes with other IPUMS India (adopted NSS) data. However, the list of source variables does neither provide the original identifiers (Household or person IDs: I do not count ‘dwelling numbers’ because they are non-existent in NSS making them useless for merging, although obviously constructed on the basis of the NSS HH ID) nor the information to construct them: in particular, the FSU number is missing.
Do you have any advice on merging IPUMS with NSS? Or on obtaining 5 digit industry codes from IPUMS?