Behaghel, Luc; Crépon, Bruno; Gurgand, Marc - Institute for the Study of Labor (IZA) - 2013
In this paper we discuss how the "encouragement design" used in randomized controlled trials can be extended to a setting with two treatments and one control group. Conditions to interpret the Two-Stage Least Squares (TSLS) estimates causally are stronger than in the case with only one treatment...