Do I have to merge NHIS data with IHIS in 2012-2016? I’m using sample adult and person core questionnaire.
I am not sure if I completely understand this question, so feel free to follow up with more detail as necessary. The IHIS (Integrated Health Interview Survey) is the old name for the IPUMS Health Surveys project. The name change is motivated by the addition of the MEPS data. So, now IPUMS Health Surveys provides data from two data sources: the NHIS and the MEPS. No merging between IHIS and NHIS should be necessary. Some background information for the NHIS samples from IPUMS Health Surveys is available here.