Many large urban school districts are rethinking their personnel management strategies, often giving increased control to schools in the hiring of teachers, reducing, for example, the importance of seniority. If school hiring authorities are able to make good decisions about whom to hire, these...

We study the returns to experience in teaching, estimated using supervisor ratings from classroom observations. We describe the assumptions required to interpret changes in observation ratings over time as the causal effect of experience on performance. We compare two difference-in-differences...