People often talk about good schools and bad schools. But how are these defined. In practice a school is considered good if its students do well on standardized achievement tests, a school is considered bad if they don't. So what determines how students do on standardized tests. Empirically in the United States systematic differences in average student achievement between schools appear to be almost entirely due to differences between the students attending each school as opposed to differences between the schools themselves.
For example suppose school A is currently considered good because its students do well and school B is currently considered bad because its students do poorly. And suppose we were to start busing all of A's current students to B and all of B's current students to A. What would we expect to happen? We would expect the students who had been doing well at A to continue to do well while attending B and the students who had been doing poorly at B to continue to do poorly at A. In other words A would now be considered a bad school and B would now be considered a good school although the teachers, administrators and physical facilities at A and B would not have changed.
Unfortunately most public debate regarding educational policy totally ignores the above giving it a surreal quality. Democrats advocate improving schools by spending more money on teachers and facilities, Republicans advocate improving schools by breaking the teacher's unions and instituting vouchers. However there is no reason to believe either plan will make any significant difference in student achievement.
The Coleman report found that schools make little difference. Kansas City is an example of the failure of vastly increased spending to improve schools.