As biomedical research with volunteers was expanded in the United States, the rule of subject selection, constituting scientific and ethical criteria, was generated in 1981 to resolve selection bias in research. Few historical studies, however, have investigated the role of this new hybrid rule in institutional review systems. This paper describes how bioethics commissions and federal agencies have created the subject selection rule based on the concept of justice. I argue that the standardization of this rule as temporal measures, linked (...) with risk-benefit assessment, has reformed the review mechanism, specifically investigators’ modification of research plans, thereby developing justice as balancing. (shrink)