Alternatives to the Randomized Controlled Trial.

Author(s): West SG, Duan N, Pequegnat W, Gaist P, Des Jarlais DC, Holtgrave D, Szapocznik J, Fishbein M, Rapkin B, Clatts M, Mullen PD

Affiliation(s): Arizona State University.

Publication date & source: 2008-06-12, Am J Public Health., [Epub ahead of print]

Publication type:

Public health researchers are addressing new research questions (e.g., effects of environmental tobacco smoke, Hurrican Katrina) for which the randomized control trial (RCT) may not be a feasible option. Drawing on the potential outcomes framework (Rubin causal model) and Campbellian perspectives, we consider alternative research designs that permit relatively strong causal inferences. In randomized encouragement designs, participants are randomly invited to participate in one of the treatment conditions but are allowed to decide whether to receive treatment. In quantitative assignment designs, treatment is assigned on the basis of a quantitative measure (e.g., need, merit, risk). In observational studies, treatment assignment is unknown and presumed to be nonrandom. Major threats to the validity of each design and statistical strategies for mitigating those threats are presented.