We exploit two unusual policy features of academic high schools in Seoul, South Korea—random assignment of pupils to high schools within districts and conversion of some existing single-sex schools to the coeducational (coed) type over time—to identify three distinct causal parameters: the...

We exploit two unusual policy features of academic high schools in Seoul, South Korea - random assignment of pupils to high schools within districts and conversion of some existing single-sex schools to the coeducational (coed) type over time - to identify three distinct causal parameters: the...

In a seminal paper, Helpman et al. (2008) demonstrate that accounting for self-selection and firm heterogeneity is crucial for obtaining unbiased estimates in the gravity equation. In this paper, we show how this insight helps solve the trade elasticity puzzle that, hitherto, trade elasticity...