If students tend to choose instructors with high teaching ability, a negative link between class size and student performance may remain obscured until this kind of sorting has been taken into account. Using data from student evaluation surveys, we confirm that it is crucial to control for...

We study the effect of standardized external tests on students’ academic outcomes. We exploit the fact that only one of the 17 Spanish regions started doing and publishing the results of standardized tests in 2005 and apply a difference-in-difference methodology using outcomes of the PISA...