The effect size was about a third of a standard deviation, which isn't huge, but isn't trivial either. Assuming it's true and genetically determined, that could

The effect size was about a third of a standard deviation, which isn't huge, but isn't trivial either. Assuming it's true and genetically determined, that could have significant effects at the aggregate level. However, a ray of hope in the study is that, even if you take its confidence intervals at face value (I don't), then there is quite a bit of room for improvement in the nurture sphere, as the black/white IQ test gap is generally much larger than this when not as carefully controlled as this study.