This paper explores the effects of peers, friends, family, IQ, and academic performance, observed in the last year of high school, on earnings at ages 35 and 53. All significantly affect earnings at both ages. The effects of IQ are much smaller than asserted in, for example, The Bell Curve, and...

Using information on birth and kindergarten start dates to generate an exogenous measure of the relative age of a student's peer group, we find that, controlling for age, females with older peers are more likely to use substances than females with younger peers. Because there is no reason to...