> I wish I could find a study of similarly smart and motivated people who decided themselves to go or not to college. As a choice.
I don't think that's actually the ideal study design you want. Any measure of intelligence/motivation is going to be imperfect, so any time you try to control for it but still allow a "free choice", that free choice will be correlated with variables that plausibly impact future success (e.g., maybe "cool, rational thought" is distinct from intelligence and motivation, and influences both the choice to go to college and long-term success).
http://blogs.discovermagazine.com/neuroskeptic/2016/04/02/co...
That said, if you're just asking whether anyone has studied the impact of attending college on lifetime earnings after controlling for several sensible variables that correlate with intelligence, the answer is "yes".
> Students who go to more selective colleges make more money later in life...This partially reflects students who go to more selective colleges being more able and ambitious, as opposed to attending a more selective college boosting one's income. How much does attending boost income? The famous paper Estimating the Return to College Selectivity Over the Career Using Administrative Earning Data (2011) by Dale and Krueger raises the possibility that on average, attending a more selective college doesn't raise earnings at all. Specifically, controlling for
> * Student high school GPA
> * Student SAT score
> * The average SAT score of the colleges that a student applied for
> * The number of applications that the student submitted
> * Various demographic factors (race, sex, parental education)
> they found that as a group, there was no statistically significant difference in income later in life between students who went to more selective colleges and students who went to less selective colleges. Their finding is somewhat robust: it's based on a large (~10k) sample size, it's true both of the class of 1976 and the class of 1989, it's true of the class of 1976 from age 25 through age 50 and it's true both of men and of women.
http://lesswrong.com/lw/k0w/how_much_does_where_you_go_to_co...
Some things to note:
(1) This sort of study is obviously the very first thing you would do if you were investigating this topic seriously, yet extremely few of the popular articles on this topic mention this study. So 99% of popular discussion on this topic is hopeless uninformed, and no one cares.
(2) In the absence of a controlled randomized trial, you can still hope for high-quality pseudo experiments using techniques like differences in differences, or the effect of arbitrary numerical cutoffs, etc.
https://en.wikipedia.org/wiki/Difference_in_differences