This study analyzes the effect of age-based retention on school achievement at different stages of education. I estimate an instrumental variable model, using the predicted probability of retention given month of birth as an instrument, while simultaneously accounting for the effect of month of birth on maturity at the time of testing. The…

School systems worldwide respond in particular ways to students' academic heterogeneity, and different countries have developed different strategies to manage such heterogeneity. Whereas some countries separate children according to distinctive educational routes (or tracks) at early ages, others rely on intensive use of grade retention, while…