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Why the US Ranks Last in Geometry
| Date: |
Tue, 01 Dec 1998 11:23:00 -0800 |
| From: |
Erwin Morton
<e-morton@worldnet.att.net> |
| Reply-To: |
emorton@bigfoot.com |
| To: |
timss-forum@rbs.org |
| CC: |
John Knight
<fathersmanifesto@yahoo.com>, |
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Patsy Wang-Iverson <wang@rbs.org>, |
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"Guy F. Brandenburg"
<guyfbran@erols.com>, |
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Mark Hall <markhall@rocketmail.com>, |
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Gerry Meisels <gmeisels@bayflash.stpt.usf.edu>, |
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Francis Gardella
<fgardell@shiva.hunter.cuny.edu>, |
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Mary Jo Powell <mpowell@sedl.org> |
For nearly two weeks, timss-forum has been dominated--to its
detriment--by a flurry of messages to and from one person. This traffic
has essentially stopped all other threads and made it difficult to
discuss anything except one man's personal agenda.
[NOTE: That
"personal agenda" was simply a request of this forum to
critique the TIMSS data displayed graphically at
http://christianparty.net/educate2.htm]
May I suggest that everyone reading or participating in this
forum would
find it instructive to look at the following web sites--the home
pages
of the sites repeatedly referenced by Mr. Knight:
http://www2.crosswinds.net/san-diego/~manifesto/
http://christianparty.net/
See also:
http://christianparty.net/listfigures.htm
In addition to the obvious I-have-a-point-to-prove orientation of
these
sites, I note that the "close correlations" referenced
by Mr. Knight
involve "selected countries", and not always the same
number of
countries. What is the basis of the selection? Has the person who
created the graphs selected the countries that best fit the
correlation
he desires?
[NOTE: All of the data
points available from TIMSS were used to create the graphs.
Anyone vaguely familiar with the data would know that not all
data is available for all countries. Erwin failed to point out a
specific data point which was available from TIMSS but which was
not used in the graphs because there were no missing data
points.]
[I believe that in this instance I can safely
use the
pronoun "he" without fear of being labeled sexist.] How
good is the
analysis of the data?
[NOTE: For what reason
would a simple request for an "honest" critique of the
data raise such ire with an educator who presumably would
appreciate the effort put forth to evaluate an education system
which spends more as a percent of GDP than most other nations,
and whose 12th graders scores LAST in geometry education?]
Here is a specific example, drawn from one of
the
web sites Mr. Knight cites:
The three graphs
http://christianparty.net/educate32.gif
http://christianparty.net/educate31.gif
http://christianparty.net/educate21.gif
all purport to show correlations between TIMSS scores and the
percentage
of male teachers, in 7, 13, and 17 countries respectively.
educate 32
(the 7-country graph) and educate31 (the 13-country graph) show
the same
7 data points; educate31 adds 6 more countries, all of which have
predominantly *male* teachers and relatively *low* TIMSS scores
(i.e.,
all six points are on the right and well below the fitted line).
Yet
the (least-squares?) fitted line is identical on the two graphs!
That
is, the extra six points have no apparent effect on the fit!
[NOTE: This ignores the
fact that it is clear from http://christianparty.net/educate32.gif that 6 of
the 7 G-7 Countries have more male teachers than the US, that all
of their 8th graders score considerably higher than the ours, and
that there is an unmistakable correlation.
The caption on educate32 (7 countries) says TIMSS scores increase
1
point for each 1% increase in male teachers, while the caption on
educate31 (13 countries), with this trend obviously weakened if
not even
reversed, says TIMSS scores increase *4* points for each 1%
increase in
male teachers! (The trend line shown on the graphs actually
increases
by about 2.5 points for every 1% increase in male teachers.)
[NOTE: This is the only
honest contribution Erwin made to the debate. He is correct. The
correlation is closer to 2.5 points than to 4 points. TIMSS
Scores increase "only" 2.5 points for each 1% increase
in the percent of male teachers.]
educate21, with more countries, adds more extreme outliers on
*both*
sides of the line, and appears, at first glance, to have a rather
low
correlation coefficient. But the same conclusion is drawn--4
points for
each 1%.
And nowhere, of course, is there a word about correlation
coefficients,
fitting methods, error bars, etc., etc., etc.
[NOTE: "Nowhere,
of course, is there a word about correlation coefficients,
fitting methods,error bars, etc., etc., etc." from Erwin.]
Even if we ignore the sloppy mathematics, it is dangerous to
select the
data that fit (or appear to fit, or can be made to appear to fit)
the
thesis one is trying to demonstrate, and ignoring or rejecting
all other
data by waving one's hand and labeling it outlying, discordant,
or
nonconforming data.
[NOTE: On what basis
can Erwin critique the data, fail to point out a single specific
error, and still expect to have his cohorts embrace him as an
"intellectual"?]
It is not a sound basis for research, for understanding, or for
policy
decisions. It is a good way to delude ourselves, and an excellent
method for deluding others (intentionally or unintentionally).
[If Erwin were really
concerned about this, he must simply point out specific data
which is missing and refrain from vague assertions that it is
"made to appear to fit".]
Remember also that even a true close correlation does not, in and
of
itself, demonstrate causality.
Pretty graphs are impressive and memorable, and may seem
convincing, but
we should be extremely cautious about accepting any of these
conclusions
without verifying that both the data and its analysis are correct
and
complete. We should also consider both what other interpretations
might
be possible, and what other research sheds light on the same
questions.
But, to quote Mr. Knight (Monday, Nov. 30):
> However, even without correcting these obvious erroneous
data points,
> there is still such a close correlation between TIMSS Scores
and the
> percent of teachers who are men that this probable factor
cannot
> continue to be ignored
> [http://www2.crosswinds.net/san-diego/~manifesto/educate32.gif.] It
> would not be appropriate to refocus the discussion on TIMSS
data at
> this point, particularly if this *is* the root of the
problem.
Yet even the graphs he cites do not confirm the correlation he
claims.
[The graphs were
reexamined for missing data, recreated to make sure nothing was
missing, and posted at http://christianparty.net/timssmaleteachersg7.htm and timssmaleteachersg7.htm so you can be the judge about
his claim that the data does not correlate.]
Again, quoting Mr. Knight:
> Such pop edudcation (sic) theories obviously don't work.
I could not agree more, but I doubt that he and I are speaking of
the same theories.
The friendly folks at US TIMSS have been careful to distinguish
among (a) what the data shows, (b) what the data suggests, (c)
what questions
the data simply does not answer, and (d) what questions the data
does not even address. I suggest we try to do the same.
[When the data from the
friendly folks at US TIMSS is crosschecked with other data
sources, the correlation looks more like timssmaleteachers.htm . I suggest we examine these
friendly folks' data a little BIT closer and question why the
data at http://nces.ed.gov/timss/twelfth/fig12.html shows that nobody in the world
scored lower in geometry than American students out of 16
countries AND WHY THE DATA FROM THE MUCH HIGHER SCORING COUNTRIES
LIKE KOREA, JAPAN, TAIWAN, HONG KONG, SINGAPORE, BELGIUM, SLOVAK
REPUBLIC, HUNGARY, AUSTRALIA, IRELAND, ISRAEL, THAILAND, AND
NORWAY IS NOT ON THIS CHART!?]
--Erwin Morton
emorton@bigfoot.com
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