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Re: st: RE: Sample size calculation


From   Ronán Conroy <rconroy@rcsi.ie>
To   <statalist@hsphsun2.harvard.edu>
Subject   Re: st: RE: Sample size calculation
Date   Wed, 26 Oct 2005 18:01:23 +0100

On 26 DFómh 2005, at 16:34, Vivian Goodell wrote:

Don't know if this would help, but we do PASS calcs for new tumor
markers like this: Set power and alpha at something reasonable
(reasonable to review boards, usually 80% and 0.05)and create a graph
showing a range of sample sizes plotted against a range of effect sizes.
As a member of a review board, running a study that has a 20% chance of failing to find a clinically important effect, if such an effect exists, is no longer acceptable. We like to see 90% or even 95% power reported. I encourage people I work with to report both. The problem in medical research (and in other areas too, I guess) is false negative findings.

Ronán Conroy
rconroy@rcsi.ie




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