I think Paul's argument is misleading. I say that as someone who went to both in high school. There are public schools that put out the best of the best (i.e magnets and magnet-like schools) and there there are private schools that are just holding pens for the spawns of the wealthy and a few talented athletes. But one thing that many private schools provide that most public schools don't is the academic agency for students to pick from a wide range of courses that match their ability and a standardized curriculum that pairs well with those choice in terms of thoroughness and rigor.

Most public high schools don't have AP or IB courses and the ones that do tend to have them in limited supply in the hard sciences ( i.e. AP Physics C, AP Computer Science A, etc). Pursuing some sense of rigor involves taking courses that seem difficult rather than taking them in the hopes of forming a more cohesive understanding for one's future pursuits. Self-teaching obviously helps quite a bit, but that doesn't aid most students in achieving a firm foundation for say, undergraduate research in Physics.

Paul Graham's assertion that 'parents send their kids to private schools to improve university admission standards' does not guarantee that 'kids from public schools are smarter than kids from private schools.'

Some private schools have high admission standards, and these have better teachers and more motivated students than comparative public schools in the area. The existence of these counter-examples shows that Graham's reasoning doesn't hold. He also assumes that the public school students have studied less material, or easier material, than private school students, and are more motivated to learn. This isn't guaranteed; certain public school programs (like IB, mentioned by another commenter here) meet or exceed the curriculum standards by other private schools. In short, the wording of the Tweets in their current form demonstrate weak reasoning.

However, to take a more charitable interpretation, it's true that other private schools let anyone in who can pay the tuition, while also having less dedicated teachers and unmotivated students compared to public schools (especially public schools with high admission standards). Using more precise language, it can be altered to roughly: "motivated but less-privileged students can outcompete less motivated, more-privileged students in university."

This is a more interesting assertion, but it also depends on the amount of privilege (e.g. some privileged students get an apartment with near-zero commute to the university, lots of cash, the best tutors, etc.). Life isn't truly meritocratic, but you try to do the best you can with the cards you're dealt.

> Paul Graham's assertion that 'parents send their kids to private schools to improve university admission standards' does not guarantee that 'kids from public schools are smarter than kids from private schools.'

You are correct. However, it does mathematically guarantee that 'kids from public schools are smarter than kids from private schools at any given university (except, maybe, one of HYPMCS)'

In any competitive market, from the perspective of a market actor, independent selected-for variables will appear to be inversely correlated.

That's correct! Thanks for your comment; I wrote the original to practice logical thinking, and your feedback is helpful for learning.

So just survivorship bias for public schooled students? I feel like this only exacerbates how public schooling is failing