Earlier quoted context omitted.
He is referring to measuring you in your time after college to see how what you gained from the experience has actually shaped your life, and if it matches what was expected from the onset. But given that you don't have a perfect clone that is in every way equal except for having gone to college, it is understandably difficult to measure. It seems, at best, we have people trying to compare the worlds best prodigies w…
The populations of both people who go to college and those who do not are so large that I feel like we could likely control for effects (at least extreme ones like you're talking about) and make useful judgments.
It's kind of like looking at the Olympics to see how it has shaped the athletic ability of the athletes compared to the ability of the population who have never been to the Olympics. You are bound to find outliers[1], but observing that Olympic athletes are usually stronger athletes might leave you to believe that going to the Olympics makes one a significantly better athlete. However, in reality, those same people would still be among the best athletes even if they never went anywhere near the Olympics.
[1] http://www.independent.co.uk/sport/olympics/winter-olympics/...