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RE: st: RE: McNemar's test with clustering


From   "Lachenbruch, Peter" <Peter.Lachenbruch@oregonstate.edu>
To   "'statalist@hsphsun2.harvard.edu'" <statalist@hsphsun2.harvard.edu>
Subject   RE: st: RE: McNemar's test with clustering
Date   Mon, 26 Apr 2010 10:36:31 -0700

Could you treat the members of the twin pairs as a block in a randomized block fashion?  The clogit idea sounds pretty good

Tony

Peter A. Lachenbruch
Department of Public Health
Oregon State University
Corvallis, OR 97330
Phone: 541-737-3832
FAX: 541-737-4001


-----Original Message-----
From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Laura Gibbons
Sent: Monday, April 26, 2010 10:10 AM
To: 'statalist@hsphsun2.harvard.edu'
Subject: Re: st: RE: McNemar's test with clustering

Sorry this wasn't clear.  For this analysis, I'm just interested in the 
men as individuals, are their right and left sides different.  If I had a 
continous outcome (and no twinship to consider), I'd use a paired t-test.

But the sample happens to be (for other reasons) twins, so I need to 
adjust errors (p-values) for the correlation between twins.

Pair	Twin	Left 	Right
-----------------------------
1	1	1	0
1	2	1	1
2	1	0	0
2	2	1	0

something like that, where I wan't to compare Left and Right, and Pair is 
a nuisance variable to me.

thank you!  Laura


On Mon, 26 Apr 2010, Lachenbruch, Peter wrote:

> I seem to be missing something here.  If you take the within-pair 
> difference aren't you removing the pair effect? You can make the same 
> argument for a dichotomous response. In this case the difference will be 
> -1, 0, or 1.  You could do a t-test on this (variance would be slightly 
> off) or you could look at the table of responses and test if the 
> proportion of -1s is the same as the proportion of +1s.  May need to do 
> this by hand, but should be simple. What is the clustering variable if 
> not pairs?
>
> Tony
>
> Peter A. Lachenbruch
> Department of Public Health
> Oregon State University
> Corvallis, OR 97330
> Phone: 541-737-3832
> FAX: 541-737-4001
>
>
> -----Original Message-----
> From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Laura Gibbons
> Sent: Sunday, April 25, 2010 6:39 PM
> To: statalist@hsphsun2.harvard.edu
> Subject: st: McNemar's test with clustering
>
> I'd like to do something like McNemar's test, -mcc-, where I'm comparing
> presence of two dichotomous traits in each person.  [In this case, is a
> finding more common on the left side of the spine, compared to the right.]
>
> The problem is that the subjects are twins, in this analysis a nuisance
> parameter, but svyset or cluster(pair) are not options for mcc.
>
> For continuous outcomes I can get the equivalent of a paired t-test by
> computing the difference and then getting the p-values from the intercept
> in
>
> reg difference, cluster(pair)
>
> but I've not come up with anything along these lines either.
>
> Any guidance would be appreciated, thanks!
>
> -Laura
>
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> Laura E. Gibbons, PhD
> General Internal Medicine, University of Washington
> Box 359780, Harborview Medical Center, 325 Ninth Ave, Seattle, WA 98104
> phone: 206-744-1842, fax: 206-744-9917, Office address: 401 Broadway, Suite 5122
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Laura E. Gibbons, PhD
General Internal Medicine, University of Washington
Box 359780, Harborview Medical Center, 325 Ninth Ave, Seattle, WA 98104
phone: 206-744-1842, fax: 206-744-9917, Office address: 401 Broadway, Suite 5122
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*
*   For searches and help try:
*   http://www.stata.com/help.cgi?search
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/

*
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*   http://www.stata.com/help.cgi?search
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/


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