More children than ever attend center-based care early in life. We study whether children who attend center-based care before age 3 have better or worse language and motor skills, socio-emotional maturity, and school readiness just before entering primary school. In data covering about 36,000...

Identification in most sample selection models depends on the independence of the regressors and the error terms conditional on the selection probability. All quantile and mean functions are parallel in these models; this implies that quantile estimators cannot reveal any - per assumption...

This paper discusses the nonparametric identification of causal direct and indirect effects of a binary treatment based on instrumental variables. We identify the indirect effect, which operates through a mediator (i.e. intermediate variable) that is situated on the causal path between the...