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st: re. case control design & analysis


From   "roger webb" <roger.webb@man.ac.uk>
To   statalist@hsphsun2.harvard.edu
Subject   st: re. case control design & analysis
Date   Wed, 2 Jul 2003 09:51:57 +0100

Dear Statalist

I have a case control study in which cases were inpatient suicides 
and eligible controls were alive and in inpatient care on the index 
date (i.e. the date of death of the corresponding case). There is no 
matching for age, sex, diagnosis, or any other explanatory variable. 

I'd greatly appreciate advice on the following two issues:

1) Is this a matched design, or does the single criterion for 
selection of controls (i.e. alive on index date) simply constitue 
sampling from the risk set (as in Clayton & Hills, 1993)? Therefore 
should I analyse the data using conditional logistic regression or 
just use the simple 'logit' / 'logistic' commands?

2) If conditional logistic regression is required, how can I perform a 
sample size calculation that accounts for matching? (I'd like to 
know the answer to this anyway, please, regardless of your 
answers to Qu.1). The 'sampsi' command doesn't appear to provide 
any options for sample size calculations with matched designs.

Thanks
Roger Webb

School of Psychiatry & Behavioural Sciences
Manchester (UK)   

  
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