Thank you Clyde! I decided to include it. Te imputation worked, so the problem is gone. Following your argumentation I don't really have a choice
. So I agree.

egen land = group(S003) su land, meanonly gen N = . forvalues i = 1/`r(max)' { capture regress educ (c.X047 c.X003 c.female)##c.wave if land==`i' if _rc == 0 { predict educ_hat if land==`i', xb replace educ = educ_hat if missing(educ) & land==`i' replace N = e(N) if land == `i' drop educ_hat } }
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