We exploit rules of class formation to identify the causal effect of increasing the number of immigrants in a classroom on natives test scores, keeping class size constant (Pure Composition Effect). We explain why this is a relevant policy parameter although it has been neglected so far. We show...

This paper presents an empirical study of birth-order and sibship sex-composition effects on educational achievement, and uses these variables as instruments to estimate returns to education, with the help of a rich set of individual data. Our sample includes more than 12,000 men and 10,000...