Chiming in a bit late here, but one of the things I found most interesting about the whole series of Globe articles is that 25% of Boston public school students attend a test/exam school, as compared with 5% in New York. It shouldn’t really come as much of a surprise if you take a quarter of the brightest, most likely to achieve students of the mix, and leave the other three quarters to muddle along in less good schools, those kids don’t later do as well. Being the parent of 3 teenagers, I can say with some assurance that having bright, motivated students around a teenager can be a significant factor in pulling up achievement. There’s something to the rising tide lifts all (or at least many) boats concept. The converse is also true – if students in non-exam schools have the perception that the school isn’t for the smart kids, guess what happens? Perception becomes reality.