The accumulated economic analysis of education suggests that current provision of schooling is very inefficient. Commonly purchased inputs to schools – class size, teacher experience, and teacher education – bear little systematic relationship to student outcomes, implying that conventional input policies are unlikely to improve achievement. At the same time, differences in teacher quality have been shown to be very important. Unfortunately, teacher quality, defined in terms of effects on student performance, is not closely related to salaries or readily identified attributes of teachers.