Maybe I’m misunderstanding the article, but I find it baffling that they don’t mention the simple fact that the “best” professors have access to the “best” students. Especially early in career students. Never mind the fact that great schools -> employ great researchers -> enroll great students, even within one cohort this is clear. The top 5% of a class can do their undergraduate research everywhere they please and are in fact often scouted out by top chairs.