Resources for Causal Reasoning in Health Services Research

Effect of treatment on treated

Heckman et al. (1997b) have argued that in a variety of policy contexts, it is the average treatment effect for the treated that is of substantive interest. The essence of their argument is that in deciding whether a policy is beneficial, the interest is whether it is beneficial for those individuals who are either assigned or who would assign themselves to the treatment, rather than whether on average the program is beneficial for all individuals.