Re: [R] Is there a non-parametric repeated-measures Anova in R ?

From: Bert Gunter <gunter.berton_at_gene.com>
Date: Wed, 16 Jun 2010 12:43:18 -0700

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-bounces_at_r-project.org [mailto:r-help-bounces_at_r-project.org] On Behalf Of Frank E Harrell Jr
Sent: Wednesday, June 16, 2010 11:31 AM
To: r-help_at_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.Galili_at_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.miles_at_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.galili_at_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.Galili_at_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_at_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_at_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

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