The one that comes to mind was the study that compared long term outcomes of students who were accepted to Harvard and attended to those who were accepted but did not attend.
Average future incomes were not statistically different.
But the study did note that the starkest improvents in future incomes were found in poor and minority students.
Either way, I'm sure having a diploma from Harvard would open some doors for pretty much anyone, and I'm not naïve enough to pretend otherwise, but I have serious doubts that a diploma from Harvard can truly tell you anything other than that person has the ability to make it through Harvards' admission filter, and do mindless homework for X number of years, like every other college.
I don’t know if this comparison controls for the confounders. Alice and Bob are both accepted to Harvard, and Alice decides to attend and Bob decides to chill out at the University of Maui for four years. That’s pretty indicative of Alice being more ambitious and achievement-oriented.
I will say I don't totally understand how future income differences can be not statistically significant and also be "stark" between lower income students at the same time.
https://www.usnews.com/education/blogs/the-college-solution/...
The no-difference in financial outcomes was based on comparing the average incomes of the two groups. So naturally, you will have outliers on both sides. They found that minority students tended to be the outliers.
Part of that probably has to do with the more prestigious school getting them a job they wouldn't have had. But also probably has to do with minority students getting access to the rich, well connected network that they wouldn't have had access to otherwise.
Edit: I believe this is it: https://www.nber.org/papers/w7322