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re: Re: Re: st: replicating 2 X 2 data from a paper


From   "Ariel Linden, DrPH" <ariel.linden@gmail.com>
To   <statalist@hsphsun2.harvard.edu>
Subject   re: Re: Re: st: replicating 2 X 2 data from a paper
Date   Thu, 4 Apr 2013 10:28:08 -0400

Thanks for the follow up, David. I came to the same conclusion that they
probably ran -tab- chi2 to get the p values, and they manually calculated
the percent difference (no relation to the p value). They certainly should
have been clear in how they got to these values, since we're only
speculating. 

Also, to you point about Poisson:  it seems that they would have been better
served using a count model than contingency tables for no other reason than
to provide the reader with contrast estimates with confidence intervals.
Testing for over-dispersion is not a difficult task, and it certainly would
not take more than a few extra minutes to complete the entire analysis.
Interestingly enough, medical journals require that papers reporting results
from an RCT show confidence intervals and not just p-values (or more
broadly, that authors follow CONSORT statement about writing up results from
RCTs). I am not sure how this slipped by.

In any case, thanks again for your second pair of eyes on this...

Ariel

Date: Wed, 3 Apr 2013 20:30:03 -0400
From: David Hoaglin <dchoaglin@gmail.com>
Subject: Re: Re: st: replicating 2 X 2 data from a paper

Hi, Ariel.



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