A compact dataset containing information on an encouragement, (Z, cholestyramine prescription), a treatment (X, usage), and an outcome (Y, cholesterol). From David Maxwell Chickering and Judea Pearl: "A Clinician’s Tool for Analyzing Non-compliance", AAAI-96 Proceedings. Chickering and Pearl in turn draw the data from Efron, Bradley, and David Feldman. "Compliance as an explanatory variable in clinical trials." Journal of the American Statistical Association 86.413 (1991): 9-17.