Private schools can provide this kind of performance for much less money than public schools. Here in Florida, it cost, on average, between $7,000 - $9,000 per student, per year. This is the whole enchilada - transportation, extracurricular activities, etc. A local church school charges $1,800 per year for each student. The parents must provide transportation, books, and some classroom materials. Other church schools charge up to $3,500 but provide busing, after-school sports, and other activities. Guess which students perform better?

Not that there's any selection bias at all here. Or that the private schools are forced by law to deal with things that the public schools are. In other words, sure, if you skim off the brightest and most motivated kids and put them in a different school, hey presto! they'll perform better than the ones left behind. This proves NOTHING about either public or private schools. Hell, it hardly even SHOWS anything, let alone prove.

Alex