( better late than never. )
This might be relevant to Steve's request.
On 1 Sep 2000 16:20:13 -0700, [EMAIL PROTECTED] (Simon, Steve, PhD)
wrote:
> I need to find a good reference that critiques the use of post hoc power
> calculations--in particular those calculations that use the observed effect
> size rather than an effect size which is clinically relevant.
>
"A note on misconceptions concerning prospective and retrospective
power," by Bruno D. Zumbo and Anita M. Hubley. The Statistician
(1998) 47, Part 2, pp. 385-388.
... ' We suggest that it is nonsensical to make power calculations
*after* a study has been conducted....' And they say, report the
effect size.
They say, "retrospective power" only makes sense in a (non-research)
setting where you know the ultimate truth and falsity.
http://www.pitt.edu/~wpilib/index.html
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