Hi there,

I have panel data with each survey providing multiple STATA datasets from that sweep.
Each household surveyed has a unique ID number, yet some of these are duplicated if two people from a household were surveyed. The ID number remains consistent for each sweep of the survey.
From data from an earlier sweep, I have data on respondent var1 (categorical). Not all respondents provided answers.
In my most recent survey data, some those who did not answer before have given an answer for their var1 in the most recent survey, whilst some again did not answer, and those who have answered before were coded as 'not applicable.'

Therefore, I wish to bring the var1 data from the previous survey into my existing most recent dataset whereby most responses are 'not applicable' due to the prior dataset containing the information. I need the var1 to correspond to the correct unique ID number, thereby replacing the 'not applicables' with the correct var1 data provided in the previous sweep, and retaining the new information provided in the most recent sweep.

Any suggestion/direction would be most appreciated! Thank you!