Skepchick Stacey has taken a look at Richard Lynn’s claims, based on IQ testing, that male geniuses outnumber female geniuses 8 to 1. It’s a good post, worth reading in its entirety. I’m going to pull out just one piece of it briefly to talk about the simple math behind the test itself.
IQ tests are deliberately designed to eliminate disparities between demographics. Any questions that test with a statistically significant difference are discarded so that the score variation can only be attributed to differences in individual intelligence. The creators of the tests don’t allow questions in which one demographic scores significantly higher or lower than another. If women consistently scored lower than men on a particular test, that test would be unmarketable because its results would be viewed as biased and invalid.
This applies to both individual (or grouped) items and to overall tests. Tests and questions are created to produce the same mean in males and females in the groups used to develop the tests. However, this means we need to take a hard look at those groups.
Of particular concern is the fact that males far outnumber females among people with learning disabilities. (They’re kind of fragile that way, among others.) In fact, the people who like to tout the genius figures will happily point to the greater representation of males at the lowest end of IQ distributions as proving that their point is somehow “fair.” This is, of course, less impressive when you consider that they don’t expect to ever find themselves in this portion of the curve.
It’s even less impressive when you consider how unfair this higher representation of males with learning disabilities causes the test to be for females without learning disabilities. I mean that literally. A population with this gender imbalance in learning disabilities requires that the test be biased against females when you compare non-disabled groups. If it isn’t, it can’t produce the same mean for both sexes.
But don’t they exclude the learning disabled when creating IQ tests? Not for Weschler tests, at least. Given that one of the main uses of IQ testing is identifying the learning disabled, there are very good reasons to include them.
So as long as IQ tests are built this way, expect them to include the kind of bias that pushes more men into the genius range. And anyone who says that this means something more than that the test is doing what it’s supposed to do? Feel free to tell them just how dumb they’re being.