The talk of education world these days in the documentary "Waiting for 'Superman.'" It shows the terrible state of the worst public schools, and some of the successful alternatives that prove that things could be better. The KIPP academies and the Harlem Children's Zone schools produce tremendous improvements in terrible neighborhoods. They succeeded where the local "dropout factories" failed.
Filmmaker Davis Guggenheim has made a powerful ideological indictment of intransigent mediocrity, especially in urban poor schools. His overall conclusion is that good teachers are the heart of good schools. This is mostly right. However, what his account of the KIPP and Harlem Children's Zone schools shows is that the culture of the whole school is vitally important - more important, on the whole, even than the quality of individual teachers.
You need both, of course. However, really great teachers - really great anything - will always be in short supply. A school can succeed with a few really great teachers, and the rest decent teachers willing to work hard - as long as it ruthlessly weeds out the few bad teachers. This creates a climate of achievement that can lift everyone's game, and improve learning for children.