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RE: st: how to deal with censoring at zero (a lot of zeroes) for a laboratory re


From   "Scott Merryman" <smerryman@kc.rr.com>
To   <statalist@hsphsun2.harvard.edu>
Subject   RE: st: how to deal with censoring at zero (a lot of zeroes) for a laboratory re
Date   Mon, 6 Jun 2005 07:27:49 -0500

> -----Original Message-----
> From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-
> statalist@hsphsun2.harvard.edu] On Behalf Of Daniel Waxman
> Sent: Monday, June 06, 2005 6:17 AM
> To: statalist@hsphsun2.harvard.edu
> Subject: RE: st: how to deal with censoring at zero (a lot of zeroes) for
> a laboratory re
> 
> Maarten, Kevin,
> 
> Thank you very much for your replies.  So for now I am just going give up
> trying to make distributional assumptions and to drop the half of the
> observations which are zero or non-detectable prior to log transforming
> the
> predictor and to creating the logistic model.  In fact, whether I do this
> or
> change the zero to half of the lowest detectable value (i.e. .005) doesn't
> have much of an effect on the logistic odds ratio.
> 
> If anybody has any objections to this (or sees how a statistical reviewer
> for a medical journal might have objections), please let me know.
> 
> Daniel
> 


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