Many North American college students have trouble satisfying degree requirements in a timely manner. This paper reports on a randomized field experiment involving two strategies designed to improve academic performance among entering full-time undergraduates at a large Canadian university. One...

Instrumental Variables (IV) methods identify internally valid causal effects for individuals whose treatment status is manipulable by the instrument at hand. Inference for other populations requires some sort of homogeneity assumption. This paper outlines a theoretical framework that nests all...