Data that includes going to college almost certainly includes SAT scores. (I also think they correlate strongly with IQ, but haven't looked for that data). I'm "sure" that the effect of more schooling is higher on those with higher SAT scores.
In addition, I'd guess the data includes average, rather than median, income increases, so it is more easily skewed upward by those achieving super-rich status (those overpaid CEOs -- yes, I do think overpaid -- for instance). Tom Grey PS. part of the great benefit of this list is that, often, asking a good question allows somebody else to answer it who has already researched it, or part of it ... so that I don't have to. I'm probably not too much of a free rider. >>> Now I won't argue that some people who get two years of college and then drop out without a degree might not have been better off getting a two year degree of certification, but the first order effect is something like at least a 6.5% increase in income for each year of school completed whether you get a degree or not. - - Bill
