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...

We study how upgrading the skills of the personnel affects a firms performance. Two different strategies are examined : 1) providing formal training and 2) strategic recruitment and separation policy. The use of register-based longitudinal employer-employee data supplemented with a survey on...