post hoc statistical power

I remember reading about post hoc statistical power on R-help.  But I
can't seem to find them with RSiteSearch("post hoc statistical power")
and variations of it.

I would like to learn more about post hoc statistical power, its
meaningfulness, advantages and disadvantages.  I thought the issue was
settled after Tukey's 1993 paper about post hoc statistical power
being "essentially meaningless once the experiment has been done".
But they seem to be used, and sometimes encouraged
(e.g., http://www.informaworld.com/smpp/content~content=a787469931).

I do not intend to start a debate.  I simply would like to learn
more.  Can anyone suggest a few articles?  Thanks,

Yuelin.

Tukey JW. Tightening the clinical trial. Control Clin Trials. 1993;14:266-285.


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-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
project.org] On Behalf Of Yuelin Li
Sent: April-08-08 12:47 PM
To: r-help at r-project.org
Subject: [R] post hoc statistical power

I remember reading about post hoc statistical power on R-help.  But I
can't seem to find them with RSiteSearch("post hoc statistical power")
and variations of it.

I would like to learn more about post hoc statistical power, its
meaningfulness, advantages and disadvantages.  I thought the issue was
settled after Tukey's 1993 paper about post hoc statistical power
being "essentially meaningless once the experiment has been done".
But they seem to be used, and sometimes encouraged
(e.g., http://www.informaworld.com/smpp/content~content=a787469931).

I do not intend to start a debate.  I simply would like to learn
more.  Can anyone suggest a few articles?  Thanks,

Yuelin.

Tukey JW. Tightening the clinical trial. Control Clin Trials.
1993;14:266-285.



=====================================================================

     Please note that this e-mail and any files transmitted with it may
be
     privileged, confidential, and protected from disclosure under
     applicable law. If the reader of this message is not the intended
     recipient, or an employee or agent responsible for delivering this
     message to the intended recipient, you are hereby notified that
any
     reading, dissemination, distribution, copying, or other use of
this
     communication or any of its attachments is strictly prohibited.
If
     you have received this communication in error, please notify the
     sender immediately by replying to this message and deleting this
     message, any attachments, and all copies and backups from your
     computer.

Another paper critical of post-hoc power calculations is Hoenig and Heisey,
2001. "The Abuse of Power: The Pervasive Fallacy of Power Calculations for
Data Analysis." The American Statistician, 55, 19-24. Hoenig and Heisey show
that so-called "observed power" is simply a re-expression of the p-value.