Thanks for the tips everyone - I'll look into MCMC sampling for the CI. As far as the power analysis goes, I'm somewhat familiar with the criticisms regarding power analysis. I think this reviewer was curious about it because there was a small sample size (small number of levels of the random effect) and the ICC point estimate was not so low as to be biologically insignificant. It would be nice to state in the paper how much larger of a sample size would have enabled us to detect an effect given the observed variation, as though this were a pilot study for planning a bigger experiment. I'll certainly bring up the suggested citations, but I would still be interested to know if there is a method available for performing a power analysis for an LRT of a random effect. Thanks again,
Brad On Thu, Apr 12, 2012 at 12:18 PM, Brian Inouye <bdino...@bio.fsu.edu> wrote: > In addition to Bob O'Hara's suggestion, here is another citation you can > give the reviewer/editor, as to why retrospective power analyses are a > waste of time. > > Hoenig, J. M. and D. M. Heisey (2001). "The abuse of power: the pervasive > fallacy of power calculations for data analysis." American Statistician > 55(1): 19 - 24. > > Last year the ESA updated its author guidelines for reporting statistics, > and removed a suggestion to report power analyses that had been inserted in > the 1980s. > > -Brian Inouye > Florida State University > Chair, statistical ecology section of the ESA > > > > On 4/12/2012 6:00 AM, > r-sig-ecology-request@r-**project.org<r-sig-ecology-requ...@r-project.org>wrote: > >> 2) A reviewer requested a power analysis of the ability to detect a >> significant random effect. Any tips on how to approach that? >> > Report the random effect and confidence intervals. Retrospective power > analyses are pretty pointless (e.g. see http://beheco.oxfordjournals.** > org/content/14/3/446.full<http://beheco.oxfordjournals.org/content/14/3/446.full>), > unless you're planning to repeat the experiment. Bob > > ______________________________**_________________ > R-sig-ecology mailing list > R-sig-ecology@r-project.org > https://stat.ethz.ch/mailman/**listinfo/r-sig-ecology<https://stat.ethz.ch/mailman/listinfo/r-sig-ecology> > -- Bradley Evan Carlson PhD Candidate Intercollege Graduate Degree Program in Ecology The Pennsylvania State University University Park, PA 16802 Email: carb...@gmail.com http://homes.bio.psu.edu/people/faculty/langkilde/index_files/carlson.htm https://sites.google.com/site/bradleyecarlson/home [[alternative HTML version deleted]] _______________________________________________ R-sig-ecology mailing list R-sig-ecology@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-ecology
