Looking back, I can see that my colleagues and I were struggling to counteract powerful tendencies that work against high student achievement in urban schools: If teachers work in isolation, if there isn't effective teamwork, if the curriculum is undefined and weakly aligned with tests, if there are low expectations, if a negative culture prevails, if the principal is constantly
distracted by nonacademic matters, if the school does not measure and analyze student outcomes, and if the staff lacks a coherent overall improvement plan — then students fall further and further behind, and the achievement
gap becomes a chasm.