This paper examines experiments on interdependent security prisoner's dilemma games with repeated play. By utilizing a Bayesian hierarchical model, we examine how subjects make investment decisions as a function of their previous experience and their treatment condition. Our main findings are...

In a well-conducted, slightly idealized, randomized experiment, the only explanation of an association between treatment and outcome is an effect caused by the treatment. However, this is not true in observational studies of treatment effects, in which treatment and outcomes may be associated...