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Re: st: diagt and accuracy


From   Ronán Conroy <rconroy@rcsi.ie>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: diagt and accuracy
Date   Fri, 10 Jun 2005 17:23:36 +0100

heg2001@med.cornell.edu wrote:

Originally I wanted to have ROC area (as calculated in -diagt-), but I was
told that with a dichotomous test ROC area wasn't relevant, ie, I didn't
have different cutpoints at which to operate the test. That's when she
mentioned accuracy defined with prevalence.

In fact, ROC area doesn't account for prevalence either...

The ROC area is still useful, because it is the Mann Whitney statistic - the probability that if a person with and a person without the condition are taken at random, the person with the condition will have the higher score. In clinical trials, it becomes the probability that a person on the superior treatment will have a superior response. Both are very useful clinical information.

r
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