[toasterlovin]

> I said that the IQ measurement is itself not worth much except as a general guide in fairly broad ranges.

IQ predicts about 30% of a whole host of life outcomes (mostly related to job performance, educational attainment, earnings, etc.). That might not seem like a whole lot, but it's the best single predictor of life outcomes that exists, aside from looking at a person's parents and siblings.

[pessimizer]

But IQ itself is predicted by parental earnings and parental educational attainment (and, IIRC, mostly by the sheer volume of reading for pleasure during childhood.)

There's a chicken/egg thing here that I think is a cart/horse thing.

[colemannugent]

Education doesn't have as much effect as you might think. It seems that nutrition has a very significant effect on IQ: https://www.sciencedirect.com/science/article/pii/0191886990...

[toasterlovin]

It has roughly 30% predictive power after controlling for the most obvious confounding factors (like the ones you mention).