Re: power in longitudinal lme

[Mike Babyak <mbabyak@nc.rr.com>]

Try the calculator at

http://www.biostat.coph.usf.edu/research/psmgold/Power/growthpower.html

It's for the SEM type of growth curve, but might still suit your purpose.

Mike Babyak

Bernd Puschner wrote:

> Dear S-Plus users,
>
> we are planning a multicenter randomized clinical trial on the effect of a
> new discharge planning protocol (primary outcome rehospitalization) in
> patients suffering from schizophrenia. We will have two groups (treatment
> and control) four centers and plan on five measurement points.
> I plan to analyze data via lme in S-PLUS (i.e. mixed effects) and need to
> conduct a power calculation for the grant application. I looked at the
> S-Plus archives but found nothing directly relating to longitudinal designs.
> Also the software designed by Steve Raudenbush (OpDes) or Roel Bosker (PINT)
> was of no help. I was told by Steve Raudenbush that there is SAS code for
> such a problem, but I do not have SAS. Did anyone ever conduct power
> calulation for a mixed effects model with more than two measurement points
> in S-Plus? Not really necessary to consider that it will be multi-site.
>
> Any help would be highly appreciated.
>
> Thanks,
>
> Bernd Puschner
>
> ____________________________________________
> Bernd Puschner
> Ulm University, Department of Psychiatry II
> Ludwig-Heilmeyer-Str. 2
> D-89312 Guenzburg/Germany
>
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