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Re: st: Unexpected behavior from svy: proportion


From   Nick Cox <njcoxstata@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: Unexpected behavior from svy: proportion
Date   Wed, 27 Mar 2013 18:14:33 +0000

Check to see if -colvar- is a string variable. If it is, try -destring-.

Nick

On Wed, Mar 27, 2013 at 6:07 PM, Sabatier, Jennifer F. (CDC/CGH/DGHA)
<fvv9@cdc.gov> wrote:
>
>
> I am trying to get simple proportions and confidence intervals and sample frequencies from a subpopulation in survey data.
>
>
> So far this works:
>
> svy, subpop(if subpop1==1 & subpop2 == 1 & subpop3 == 1): tab rowvar colvar, ci per col obs missing nolabel
>
> Then I saw I could use svy: prop.  I'm a very novice user, by the way, though I am very skilled in SAS and R. R is my go-to program and I use it most of all.  But a lot of my collaborators use Stata so I translate code when necessary, and will perform analyses in Stata if asked.  I mention all of that so you'll know I am not totally unfamiliar with statistical programming.
>
> In this case, the original code was in SAS:
>
> proc surveyfreq data=dta missing;
> cluster psu;
> weight wght;
> tables subpop1*subpop2*subpop3*rowvar*colvar / cl(type=logit) col;
> run;
>
>
> So, the svy: tab code gives me very similar results as proc surveyfreq.  One thing that's different is the while they both give the same SE, the confidence intervals in Stata are slightly narrower than those from SAS.  But that's not why I'm here.
>
> A colleague of mine who uses Stata regularly advised I try svy:prop.  So I did and I failed.
>
>
> This is the code:
>
> svy: mean colvar , over(subpop1 subpop2 subpop3 rowvar)
>
> But it doesn't work.  I get this error:
>
> no observations
> r(2000);
>
> Where error 2000 is:
>
> error . . . . . . . . . . . . . . . . . . . . . . . . Return code 2000
>         no observations;
>         You have requested some statistical calculation and there are
>         no observations on which to perform it.  Perhaps you specified
>         if or in and inadvertently filtered all the data.
>
> So, I am obviously not understanding how to do this.  My  colleague isn't around to help me so I thought I'd turn here.  Can someone help me replicate the proc surveyfreq and/or the svy: tab using svy: prop?

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