Current procedures for soliciting consent usually do not include any attempt to determine whether prospective experimental subjects have an understanding that is adequate for informed consent. We propose that potential subjects be given a questionnaire to check how well they understand the information that has been presented to them and that this questionnaire be an additional part of the consent process.The informed consent of subjects has become increasingly recognized as a requirement for the ethical implementation of experimentation with human beings. Informed consent can serve several functions: it permits the potential subject to exercise his right of self-determination; it . . .