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Re: st: svy subpop option and e(sample)
From
Richard Williams <[email protected]>
To
[email protected]
Subject
Re: st: svy subpop option and e(sample)
Date
Wed, 25 May 2011 10:10:11 -0500
At 06:20 PM 5/24/2011, Steven Samuels wrote:
Just to elaborate: with sub-populations, the ratio estimator of a
mean with every sample member in numerator and denominator is
necessary because the sample size of the subpopulation is random,
not fixed. This extends to the regression estimators, as they are
functions of means. If you had use an -if- qualifier to restrict
the analysis to black==1, e(sample) would work as you expect; the
estimates would be the same; but the standard errors would be different.
Steve
[email protected]
As a sidelight, one of the things that has always bothered me about
subpop is that you are apparently never supposed to create an extract
from your data, e.g. you could have 100 million cases and only be
interested in a subpopulation of 10,000, but you are nonetheless
supposed to keep all 100 million cases in your data set so the
standard errors are right. I always wonder how horrible it would be
if you just made the extract or used -if- instead of subpop. If, say,
the standard errors might be off by .01%, I suspect I could live with that.
-------------------------------------------
Richard Williams, Notre Dame Dept of Sociology
OFFICE: (574)631-6668, (574)631-6463
HOME: (574)289-5227
EMAIL: [email protected]
WWW: http://www.nd.edu/~rwilliam
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