[ note, Jay: HTML-formatting makes this hard to read ]
On 11 May 2001 00:30:06 -0700, [EMAIL PROTECTED] (Jay Warner) wrote:
[snip, HTML header]
> I've had occasion to talk with a number of educator types lately, at different
> application and responsibility levels of primary & secondary Ed.
> Only one recalled the term, regression toward the mean. Some (granted,
> the less analytically minded) vehemently denied that such could be causing
> the results I was discussing. Lots of other causes were invoked.
> <p>IN an MBA course I teach, which frequently includes teachers wishing
> to escape the trenches, the textbook never once mentions the term.
> I don't recall any other intro stat book including the term, much less
> an explanation. The explanation I worked out required some refinement
> to become rational to those educator types (if it has yet :).
- I am really sorry to learn that -
Not even the texts! that's bad.
By the way, there are two relevant chapters in the 1999 history,
"Statistics on the Table" by Stephen Stigler (see pages 157-179).
Stigler documents a big, embarrassing blunder by a noted
economist, published in 1933. Horace Secrist wrote a book with
tedious detail, much of it being accidental repetitions of regression
fallacy. Hotelling panned it in a review in JASA. Next, Secrist
replied in a letter, calling Hotelling "wholly mistaken." Hotelling
tromped back, " ... and when one version of the thesis is interesting
but false and the other is true but trivial, it becomes the duty of
the reviewer to give warning at least against the false version."
Maybe Stigler's user-friendly anecdote will help to spread the
lesson, eventually.
> <p>So I'm not surprised that even the NYT would miss it entirely.
> Rich, I hope you penned a short note to the editor, pointing out its presence.
> Someone has to, soon.
I did not write, yet. But I see an e-mail address, which is not usual
in the NYTimes. I guess they identify Richard Rothstein as
[EMAIL PROTECTED]
because this article was laid out as a feature (Lessons) instead of an
ordinary news report. I'm still considering what I should say, if
someone else doesn't tell me that they have passed the word.
> <p>BTW, Campbell's text, "A primer on regression artifacts" mentions a
> correction factor/method, which I haven't understood yet. Does anyone
> in education and other social science circles use this correction, and
> may I have a worked out example?
Since you mentioned it, I checked my new copy of the Campbell/ Kenny
book. Are you in Chapter 5? There is a lot going on, but I don't
grasp that there is any well-recommended correction. Except, maybe,
Structural-equations-modeling, and they just gesture vaguely in the
direction of that.
Give me a page number?
I thought that they re-inforced my own prejudices, that when two
groups are not matched at Pre, you have a lot of trouble forming clear
conclusions. You can be a bit assertive if one group "wins" by all
three standards (raw score, change score, regressed-change score),
but you still can't be 100% sure.
When your groups don't match, you draw the graphs to help you
clarify trends, since the eyeball is great at pattern analysis.
Then you see if any hostile interpretations can undercut your
optimistic ones, and you sigh regrets when they do.
> <p>Jay
> <p>Rich Ulrich wrote:
> <blockquote TYPE=
[ snip, my earlier note, with HTML format imposed. ]
--
Rich Ulrich, [EMAIL PROTECTED]
http://www.pitt.edu/~wpilib/index.html
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