Sunday, January 28, 2007

Charles Murray on IQ again

Charles Murray got more controversy than he wanted in The Bell Curve, and is writing about IQ again:
Some say that the public schools are so awful that there is huge room for improvement in academic performance just by improving education. There are two problems with that position. The first is that the numbers used to indict the public schools are missing a crucial component. For example, in the 2005 round of the National Assessment of Educational Progress (NAEP), 36% of all fourth-graders were below the NAEP's "basic achievement" score in reading. It sounds like a terrible record. But we know from the mathematics of the normal distribution that 36% of fourth-graders also have IQs lower than 95.

What IQ is necessary to give a child a reasonable chance to meet the NAEP's basic achievement score? Remarkably, it appears that no one has tried to answer that question. We only know for sure that if the bar for basic achievement is meaningfully defined, some substantial proportion of students will be unable to meet it no matter how well they are taught. As it happens, the NAEP's definition of basic achievement is said to be on the tough side. That substantial proportion of fourth-graders who cannot reasonably be expected to meet it could well be close to 36%.
One the arguments against the validity of the IQ concept is that it is based on cognitive tests like the ETS SAT tests, and not related to neurobiological research on the brain. But there is actually a lot of research relating IQ to neurobiology, as is summarized in this 2004 review.

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