[R-sig-eco] Power analysis on mixed model

[Sebastian P. Luque]

On Thu, 18 Dec 2008 10:23:33 +1100,
"Caitlin Vertigan" <caitlin.vertigan at gmail.com> wrote:

> Hi all, I've just completed an analysis of short-tailed shearwater
> breeding success in relation to human disturbance using a mixed model.
> I'd like to do a power analysis on this now but am unaware of any way
> to do it.  Is it possible? Does anyone have any ideas?  Thanks,
> Caitlin

Are you sure you want to do that?  I was asked to provide power
calculations for other types of models in a manuscript not long ago, and
did a bit digging on this topic in general.  I'm not sure what the
consensus is now, but the following paper:

Hoenig, J. M. & Heisey, D. M. The abuse of power: the pervasive fallacy
of power calculations for data analysis Amer Statistician, 2001, 55,
19-24

is very convicing in showing that post-hoc power analyses are very
misleading.  In the mixed-effects modelling context, you might want to
use a simulation approach as that presented by:

Baayen, R. H.; Davidson, D. J. & Bates, D. M. Mixed-effects modeling
with crossed random effects for subjects and items J Mem Lang, 2008, 59,
390-412


-- 
Seb