There is at present no way to accurately compare schools. As a nation, we've just begin to consider valid ways in which schools' can be judged. If the schools were in the same states, you could get hold of their results on the state tests but the results of such tests now only show what we've long known - schools in richer areas have students who do better on tests.

Indeed, that's the only statistic that does work - if you have to choose between schools and if you choose the school in the more affluent area, that school's test scores will be better. And on every test. State tests, SATS, ACTS.