Collective equipoise, disappointment, and the therapeutic misconception: on the consequences of selection for clinical research.

Private information induces individuals to self-select as subjects into clinical research trials, and it induces researchers to select which trials they conduct. The authors show that selection can induce ex ante therapeutic misconception and ex post disappointment among research subjects, and it undermines the rationale of collective equipoise as an ethical basis for clinical trials. Selection provides a reason to make nontrivial payments to subjects, and it implies that researchers should not design experiments to maximize statistical power.