>Subject: Re: (none)
>From: Rich Ulrich [EMAIL PROTECTED]
>Date: 5/10/2001 5:15 PM Eastern
<Snip?
>CH: " Why do articles appear in print when study methods, analyses,
>results, and conclusions are somewhat faulty?"
>
> - I suspect it might be a consequence of "Sturgeon's Law,"
>named after the science fiction author. "Ninety percent of
>everything is crap." Why do they appear in print when they
>are GROSSLY faulty? Yesterday's NY Times carried a
>report on how the WORST schools have improved
>more than the schools that were only BAD. That was much-
>discussed, if not published. - One critique was, the
>absence of peer review. There are comments from statisticians
>in the NY Times article; they criticize, but (I thought) they
>don't "get it" on the simplest point.
>
>The article, while expressing skepticism by numerous
>people, never mentions "REGRESSION TOWARD the MEAN"
>which did seem (to me) to account for every single claim of the
>original authors whose writing caused the article.
<Snip>
>Rich Ulrich, [EMAIL PROTECTED]
>http://www.pitt.edu/~wpilib/index.html
>
The link to the NY Times story, Rich cites is below. The design of this study
certainly appears to be a candidate for the regression fallacy. After vouchers
were introduced in FL, the failing schools improved faster than the almost
failing schools: "On the eve of Congressional debate over President Bush's
plan to give students at low-performing schools federal money for private
school tuition vouchers, Dr. Greene announced that Mr. Bush's proposal would
work as well." ..."That's not a theory," Dr. Greene stated, "but proven
fact."..." [Dr. Greene] showed that after failing one time, higher-scoring F
schools posted greater gains than lower-scoring D schools. Because these
schools were otherwise alike, Dr. Greene stated that a threat of vouchers must
have made F schools improve more rapidly."
Regression to the mean can be difficult to control, but in this case there was
an internal control. In a reanalysis of the Florida school test data, Harris
found that the greater improvement of the worst schools between grading periods
was just as great during the pre-voucher period: "Dr. Harris found that before
1999, higher-scoring schools in the failing group also gained more than
lower-scoring schools in the next group. The subsequent voucher policy
apparently had no added effect."
http://www.nytimes.com/2001/05/09/national/09LESS.html?searchpv=site01
I wonder if "regression to the mean" will make it into the Congressional debate
of the education bill in the coming weeks.
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