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Re: st: Questions about svy commands
On Feb 10, 2008, at 7:12 AM, Ana Gabriela Guerrero Serdan wrote:
They are difined by province but also by urban/rural.
So I would need to include dummies for urban areas as
well, I suppose?
If each province is split into urban/rural you  have (no. strata)= (2  
x no. provinces). You could use -xi- and include all strata with  an  
i.urban*i.rural term.  You might not need the interaction term. In  
that case, modify the degrees of freedom by subtracting only the  
number of interaction terms.  If I = number of provinces, the number  
of interaction terms is I - 1.
Another issue is that I also run regressions for
different groups within my sub-sample of children. So
I have split children into 4 cohorts and in the areas
where they reside. So my regressions are a sub-sub of
the whole sample. This sounds confusing but the idea
is to use a diffs-diffs estimators. So I compare
cohorts in different areas.
You probably don't need other -subpop- statements.  For example, if  
you are computing or comparing means for several cohorts, you could  
have:
svy, subpop(children): mean varx, over(cohort)
-Steven
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