How many teachers stay, especially in the schools that need them most? The question has attracted widespread attention as policymakers have recognized that expert teaching is the most important school-related factor in student achievement. Data show that poor and minority students assigned to ineffective teachers lag significantly behind their…

A major strand in the current national push to improve secondary education is the movement to scale down schools into smaller, more personalized units, especially for students facing the greatest obstacles to success. Hundreds of small schools and learning communities have cropped up in recent years, famously helped along by the Bill & Melinda…