Actually, as Half Sigma likes to point out, that isn't what Dale and Krueger found in their study of 1976 students, that's only true when they adjusted for SAT scores and GPA and what I would call ambitiousness (by taking into account colleges applied to).
Now Dale and Krueger are back, looking at the 2007 incomes of people who applied to a couple of dozen selective colleges in 1989:
Specifically, for the 1976 and 1989 cohorts, attending a college with a 100-point higher SAT score [on a 400 to 1600 scale] lead [sic] to students receive about 6 percent higher earnings (in 1995 and 2007 respectively) according to results from the basic model ...On the other hand:
Indeed, the finding that the average SAT score of the highest ranked school that rejected a student is a much stronger predictor of that student's subsequent earnings than the average SAT score of the school the student actually attended should give pause to those who interpret conventional regression-based estimates of the effect of college characteristics as causal effects of the colleges themselves. ...So, applying to Harvard is a better predictor of future income, all else being equal, than attending Harvard. I suspect that how much money somebody makes correlates to a surprising extent with how much money they expect to make and/or think they deserve to make, which, in turn, does correlate with applying to Harvard.
About 35 percent of the students in each cohort in our sample did not attend the most selective school to which they were admitted.