AN 'INVERSIVE RISK-RATING' SYSTEM IS THEN PROPOSED AS A BASIS OF A REGULATORY MECHANISM FOR DETERMINING THE PROPRIETY OF SPECIFIC RESEARCH PROPOSALS IN GIVEN SETTINGS. UNDER THIS SYSTEM, EXPERIMENTS WOULD BE RATED FOR THE POTENTIAL PHYSICAL RISK IMPOSED ON PRISONERS AND PENAL SETTINGS WOULD BE RATED FOR THE 'RISK OF ETHICAL IMPAIRMENT' INHERENT IN THEIR CHARACTERISTICS. THE PURPOSE WOULD THEN BE ASSURANCE OF AN INVERSE RELATIONSHIP BETWEEN THE LEVELS OF PHYSICAL AND ETHICAL RISK. THE MORE THE CHARACTERISTICS OF AN INSTITUTIONAL SETTING COMPROMISE THE INMATES' EXERCISE OF FREE AND INFORMED DISCRETION OVER THEIR PARTICIPATION IN RESEARCH, THE LOWER THE RISK OF EXPERIMENTS WHICH WOULD BE PERMITTED THERE. CONVERSELY, THE MORE CLOSELY INSTITUTIONAL CONDITIONS APPROXIMATE CONDITIONS IN THE FREE LIVING WORLD, THE HIGHER THE RISK OF EXPERIMENTATION PERMITTED. A FIVE-PAGE BIBLIOGRAPHY IS INCLUDED. (AUTHOR ABSTRACT MODIFIED)