In article
<[EMAIL PROTECTED]>,
<[EMAIL PROTECTED]> wrote:
> Hi Dennis et al.
>
> The best reference concerning regression to the mean(rtm) is Dave
Kenny!
> Bookmark his homepage:
> http://nw3.nai.net/~dakenny/kenny.htm
> (Its an exciting one for still others reason than rtm )
> Dave had finalized a book about rtm which he had started to write
which the
> late Don Campbell,
<Snip>
I've ordered Kenny's book on rtm from Amazon.com (another $32 to
them; if they fail it's not due to me!). Kenny provides a link to a
wonderful description of the regression to the mean phenomenon by Bill
Trochim:
http://trochim.human.cornell.edu/kb/regrmean.htm
I believe that rtm must be happening in the MA MCAS test-retest
evaluation program, but the pattern is difficult to discern because the
Mass Dept. of education doesn't provide the scores in a fashion that are
easy to analyze. I don't see how you can plot the 1998 vs 1999-2000
socres with the available data, and this plot is the key to recognizing
rtm. The MA DOE report only whether the good performing schools met
their 2 point increase and whether the bad schools met the 6 point goal
increase (on a 200 to 280 point scale). So, rtm would make it less
likely that the top schools would meet the 2-point increase, even if
there was an overall 2 pt increase in scores state-wide. Evidence for
rtm in the poor performing schools might be masked by the need to
demonstrate a 6-point increase in scores to meet the test-retest goal.
I've requested the raw data from the MA DOE to answer some of these
questions.
--
Eugene D. Gallagher
ECOS, UMASS/Boston
Sent via Deja.com
http://www.deja.com/
=================================================================
Instructions for joining and leaving this list and remarks about
the problem of INAPPROPRIATE MESSAGES are available at
http://jse.stat.ncsu.edu/
=================================================================
