Rationale for the use of passive consent in smoking prevention research: politics, policy, and pragmatics.

The empirical evaluation of school-based smoking prevention programs requires a broad sampling of subjects who are exposed to treatment or control conditions. The low base rate of ongoing smoking among young adolescents, the slow increase in smoking rates, and concerns about the representativeness of samples make it imperative that assessment of smoking and drug use include almost all students. Positive consent procedures outlined by regulations for the protection of human subjects (Department of Health and Human Services. Code of Federal Regulations, Part 46: Protection of Human Subjects. #45 CFR 46, 1983) require parental permission for minors to participate in a research project. However, those subjects who are at highest risk to smoke are least likely to have parental consent for such a project. Low participation rates and subject selection bias are serious threats to the external validity of studies that use a positive consent procedure. With passive consent, parents respond only if they wish to withhold consent; a nonresponse is interpreted as approval of their child's participation. The subject retains the right to consent or decline participation. Four criteria must be met to waive the requirement of positive parental consent. The passive consent procedure, as used in smoking prevention research, meets those criteria. Data are presented that support the use of this procedure. Research is recommended to examine how consent procedures can affect the results of prevention studies.