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Posted at 10:00 AM ET, 12/ 3/2010

Was achievement gap understated?

By Valerie Strauss

This post was written by Richard Innes, education analyst for the Bluegrass Institute for Public Policy Solutions.

By Richard Innes
I’m used to getting bad data from Kentucky’s educators, but this time it’s the National Center for Education Statistics that messed up.

In a new set of web pages that accompanied the recent release of 12th grade National Assessment of Educational Progress reading and math scores from 2009, the NCES included a graph supposedly showing the proficiency gaps between whites, blacks and Hispanics for fourth grade math.

The only problem is that NCES officials used the wrong numbers!

While the graph is technically correctly labeled, the NCES’ graph totally ignores the kids who score at or above NAEP "Advanced." NCES only shows the percentage of kids who score at "Proficient."

The result is that the real black-white proficiency gap is understated for 2009 by a significant amount. The real gap is 30 percent larger than the gap shown on the NCES graph.

For all the details including comparison graphs go to:


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By Valerie Strauss  | December 3, 2010; 10:00 AM ET
Categories:  Achievement gap  | Tags:  achievement gap, bluegrass institute, education statistics, naep, national assessment of educational progress, nces  
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This really isn't news.

Anyone who's paying attention knows that there's a proficiency gap and there's an achievement gap. They are not the same.

NCES didn't use the wrong numbers. They just weren't saying what you thought they were saying.

Posted by: hainish | December 4, 2010 11:37 AM | Report abuse

The proper way to compare group differences in performance on cognitive tests is to measure the differences in standard deviation (SD) units, usually using "standard scores", also known as "IQ metric scores", with the reference group (usually the White population) set at 100 and then with 15 points equaling one standard deviation. So a person scoring two SD above the White average would have a score of 130, two SD below would be 70, and so forth.

It is well known that ethnoracial groups differ in general cognitive ability (IQ-type general intelligence) with American Blacks scoring about 1.0 to 1.2 SD lower on average than American Whites, thus in the USA the average Black IQ is about 82 to 85 (compared to Whites at 100, Hispanics at about 88, and East Asians at about 106).

Scores on all types of cognitively-demanding tests show strong correlations with one another. In fact studies by human intelligence experts (John DeFries, Ian Deary, Dorret Boomsma, and most prominently Robert Plomin) have shown that the same genes that modulate IQ test score differences also modulate performance on mathematics tests. Professor Plomin refers to these IQ and Math modulating genes as "generalist genes for g" ("g" is the scientific symbol for general intelligence).

The data for NAEP tests is available online at the NCES website and the scores can be obtained in the form of average scale scores with standard deviations.

Here are the NAEP Math data (the same data that Richard Innes showed in his graphs) expressed in the form of the IQ metric scores (Whites = 100, 15 points = 1.0 SD).

Notice that the average score for Math ability for Blacks is about 84 (thus matching their average IQ score which also is about 84) and for Hispanics it is 87.4 also closely matching their average IQ score.

4th Grade Math
1990 1992 1996 2000 2003 2005 2007 2009 /Average
White 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 /100.0
Hispanic 90.1 86.6 86.0 86.0 87.4 87.8 87.3 88.0 /87.4
Black 84.0 81.9 83.4 83.7 84.2 84.7 84.6 84.9 /83.9

8th Grade Math
1990 1992 1996 2000 2003 2005 2007 2009 /Average
White 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 /100.0
Hispanic 89.1 86.9 86.2 86.4 86.8 87.8 88.0 88.1 /87.4
Black 85.3 82.0 82.0 82.6 83.8 84.7 85.5 85.5 /83.9

Thus it is quite evident that ethnoracial group differences in Math ability are highly related to ethnoracial group differences in general cognitive ability.

Variation in general cognitive ability is highly heritable (genetically determined).

Now perhaps you can see why anyone who claims that ethnoracial group differences in math ability (i.e. racial "academic achievement gaps") can be eliminated by firing "bad teachers", more preschools, smaller classrooms...whatever... is just spouting nonsense. It is clear that ethnoracial groups differ in basic intelligence, HUMANS ARE DIVERSE!!! and there is no way to change that fact of human nature.

Posted by: rifraf | December 4, 2010 10:01 PM | Report abuse

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