So it still is fair to say that when we make even just crude
adjustments for ethnic demographics, we see the US pubic school system
doing as well as just about any other school system *covering an
entire country* in the world.
Huh? You just compared U.S. Whites to the entire population of a few hand picked countries. Nothing you've said here is "fair to say". The average of the whole U.S. is 509 and that of whites only is 530. 21 measly points. Why even bother saying "Whites only"? The skewing you are doing for 21 points isn't worth the humiliation when you realize that the top countries have averages in the 600's.