I worked at a private K-12 school overseas for a few years which was brutally competitive. We would very excitedly publish our excellent college admissions resu

I worked at a private K-12 school overseas for a few years which was brutally competitive. We would very excitedly publish our excellent college admissions results and would always be featured prominently in lists ranking private schools in the city and the country. The dirty little secret is that only about 70% of kids who enrolled in the first-year of the HS would actually graduate from the school. I do think the teachers we had were excellent and did a phenomenal job, but the school was designed to be impossibly difficult. The thing is, with the high reputation, the spots made available by these kids were easily filled by families wanting to send their kids in. It created a nice self-fulfilling prophecy. Anyone who has looked at school (K-12 or universities) carefully and is being honest with themselves, this sort of selection -- in all the many forms it takes -- is the real driving force behind the difference in outcomes observed in student's life-paths post-graduation.