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Re: st: Testing dependence in a 2x2 table for clustered observations


From   "Joseph Coveney" <jcoveney@bigplanet.com>
To   <statalist@hsphsun2.harvard.edu>
Subject   Re: st: Testing dependence in a 2x2 table for clustered observations
Date   Thu, 26 Aug 2010 14:19:06 +0900

Joseph McDonnell wrote:

I'm not sure I agrees with Steve here. Maybe I don't understand how he
would stratify, but I can't see that stratification would solve the
lack of independence. Personally, I'd just use the multilevel
approach. Yes, walnut meets sledgehammer...

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

You can see how you'd stratify in the example do-file below.  The illustration
uses Adriaan's variable names and 20 clinics.

Stratification is pretty conventional in this circumstance.  The do-file also 
shows the multilevel approach.  You can compare the two to see whether there's a
difference in the message.

Joseph Coveney

clear *
set more off
set seed `=date("2010-08-26", "YMD")'
set obs 20
generate byte clinic = _n
forvalues treatment = 0/1 {
    generate byte count0`treatment' = ceil(50 * runiform())
    generate byte count1`treatment' = 50 - count0`treatment'
}
reshape long count0 count1, i(clinic) j(treatment)
reshape long count, i(clinic treatment) j(recovered)
cs recovered treatment [fweight = count], by(clinic) or
mhodds recovered treatment [fweight = count], by(clinic)
expand count
drop if count == 0
xtlogit recovered treatment, i(clinic) fe or nolog
xtlogit recovered treatment, i(clinic) re or nolog
exit


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