Re: st: Survey analysis: Why does PSU affect proportions?

["Austin Nichols" <austinnichols@gmail.com>]

Craig--
Your number of obs changed when including PSU/stratum vars.
Try -codebook psu strat- to see # of missing values, etc.

On 7/10/06, Craig Anderson <clanders@uci.edu> wrote:
> I am using a published dataset (from CDC) and I want to verify that I
> can duplicate the published results before I begin my analysis.  I
> found that including clustering and stratification variables changed
> proportions, not only standard errors.  In the output that follows, I
> first used only the weights.  This gives results that agree with the
> published estimates of the proportions (produced using SUDAAN).  Next
> I used the PSU and STRATA, and get different proportions, but
> confidence intervals that agree with the published results, with
> minor variations in other runs.  I don't think the clustering by
> strata and psu should influence proportions, only their variance.
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