Last week Heritage Foundation scholar Jason Richwine, coauthor of a hotly disputed new study on the fiscal costs of comprehensive immigration reform, resigned his position in a hail of controversy over his 2009 Harvard Ph.D. dissertation. In that dissertation Richwine had argued, among other things, that American “Hispanics” are less intelligent than native-born whites as evidenced by their lower average scores on IQ tests. Richwine then attributed Hispanics’ alleged intellectual inferiority at least partly to genetic factors.

The Richwine affair is just the latest flap in a long-running dispute over the significance of IQ tests and group differences in IQ scores. It’s easy enough to shut down that debate with cries of racism, but stigmatizing a point of view as morally tainted isn’t the same thing as demonstrating that it’s untrue. Here I want to explain why Richwine’s position is intellectually as well as morally unsound.