We analyze the effects of several class compositional dimensions on individual student achievement. We make use of a rich dataset that allows tackling major endogeneity concerns stemming from non-random allocation of students between and within schools. We find that increasing the percentage of...

Being the youngest in a cohort entails many penalties. Using administrativedata of every public-school student in Portugal, we show that although performancegains from being 1-year older fade quickly from primary education to high school,age-related penalties persist through a combination of...