Frank: See section 9.2. "Efficiency and it's Deficiencies" of Cuthbert Daniel's "Application of Statistics to Industrial Experimentation" (1976, Wiley -- alas, probably now out of print).
Admittedly a different context, but statistical efficiency (aka "power") is not a transcendent virtue. Robustness (in various manifestations) counts also. Remember also that in reality, P values are typically biased low due to lack of independence: experimenter almost never randomize; studies are conducted in "convenience" order (often by necessity). Methodology that is less sensitive to this, perhaps sacrificing an illusory power, may be preferable. I do not claim anything about what's better in the current case. I just wish to caution against excessive religious orthodoxy. Cheers, Bert Bert Gunter Nonclinical Biostatistics 467-7374 http://devo.gene.com/groups/devo/depts/ncb/home.shtml -----Original Message----- From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On Behalf Of Frank E Harrell Jr Sent: Wednesday, June 16, 2010 11:31 AM To: r-help@r-project.org Subject: Re: [R] Is there a non-parametric repeated-measures Anova in R ? The Friedman test lacks power. When there are only 2 blocks it reduces to the inefficient sign test. Frank On 06/16/2010 12:43 PM, Tal Galili wrote: > Hello Jeremy, > Thank you for replying. > > I came across friedman test (I even wrote and published R code to easily > perform a post-hoc analysis of friedman > test<http://www.r-statistics.com/2010/02/post-hoc-analysis-for-friedmans-tes t-r-code/> > ). > But what I am after is *multi-way* repeated-measures anova. Thank you for > your reply which allowed me to clarify my intentions. > > Best, > Tal > > > > > ----------------Contact > Details:------------------------------------------------------- > Contact me: tal.gal...@gmail.com | 972-52-7275845 > Read me: www.talgalili.com (Hebrew) | www.biostatistics.co.il (Hebrew) | > www.r-statistics.com (English) > ---------------------------------------------------------------------------- ------------------ > > > > > On Wed, Jun 16, 2010 at 8:30 PM, Jeremy Miles<jeremy.mi...@gmail.com>wrote: > >> It's possible to use the ordinal regression model if your data are >> ordered categories. The standard non-parametric test is the Friedman >> test. >> >> ?friedman.test >> >> Jeremy >> >> >> On 16 June 2010 10:22, Tal Galili<tal.gal...@gmail.com> wrote: >>> Hello Prof. Harrell and dear R-help mailing list, >>> >>> I wish to perform a non-parametric repeated measures anova. >>> >>> If what I read online is true, this could be achieved using a mixed >> Ordinal >>> Regression model (a.k.a: Proportional Odds Model). >>> I found two packages that seems relevant, but couldn't find any vignette >> on >>> the subject: >>> http://cran.r-project.org/web/packages/repolr/ >>> http://cran.r-project.org/web/packages/ordinal/ >>> >>> So being new to the subject matter, I was hoping for some directions from >>> people here. >>> >>> Are there any tutorials/suggested-reading on the subject? Even better, >> can >>> someone suggest a simple example code for how to run and analyse this in >> R >>> (e.g: "non-parametric repeated measures anova") ? >>> >>> I waited a week to repost this question. If I should have waited longer, >> or >>> not repost this at all - then I am truly sorry. >>> >>> Thanks for any help, >>> Tal >>> >>> >>> >>> >>> >>>> >>>> ----------------Contact >>>> Details:------------------------------------------------------- >>>> Contact me: tal.gal...@gmail.com | 972-52-7275845 >>>> Read me: www.talgalili.com (Hebrew) | www.biostatistics.co.il (Hebrew) >> | >>>> www.r-statistics.com (English) >>>> >>>> >> ---------------------------------------------------------------------------- ------------------ >>>> >>>> >>>> >>> >>> [[alternative HTML version deleted]] >>> >>> ______________________________________________ >>> R-help@r-project.org mailing list >>> https://stat.ethz.ch/mailman/listinfo/r-help >>> PLEASE do read the posting guide >> http://www.R-project.org/posting-guide.html >>> and provide commented, minimal, self-contained, reproducible code. >>> >> >> >> >> -- >> Jeremy Miles >> Psychology Research Methods Wiki: www.researchmethodsinpsychology.com >> > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. > -- Frank E Harrell Jr Professor and Chairman School of Medicine Department of Biostatistics Vanderbilt University ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
