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Re: st: multiple weights per person in GEE?


From   "Joseph Coveney" <jcoveney@bigplanet.com>
To   <statalist@hsphsun2.harvard.edu>
Subject   Re: st: multiple weights per person in GEE?
Date   Thu, 23 Jul 2009 02:30:38 +0900

Ariel Linden wrote (excerpted):

Here is the code I used for the comparative models GLM in Stata vs GEE in SAS.

[output redacted]

--------------------------------------------------------------------------------

No answers--just a few observations:

1.  You've got Stata and SAS fitting different models (compare the values for
scale).  SAS is fitting with an exchangeable working correlation, and Stata is
fitting with an independent working correlation.  Is the exchangeable working
correlation essential?  If not, then try TYPE=IND or CORR=IND on the REPEATED
statement in PROC GENMOD.

2.  PROC GENMOD prints out two sets of coefficients and standard errors, as I
recall, one with "model based" and the other with "empirical" standard errors.
The latter is what I assume you're showing.  (The table's header got cut off in
the cut-and-paste).

3.  Use [pweight = iptw], not [aweight = iptw].  It couldn't hurt to use the
correct weighting scheme.

Joseph Coveney



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