Designing medical and educational intervention studies. A review of some alternatives to conventional randomized controlled trials.

The advantages and limitations of RCT designs are discussed, and a range of alternative designs for medical and educational intervention studies considered. Designs selected are those that address the much neglected psychological issues involved in the recruitment of patients and allocation of patients to treatments within trials. Designs include Zelen's (18) randomized consent design, Brewin and Bradley's (20) partially randomized patient-centered design, and Korn and Baumrind's (21) partially randomized clinician-centered design. The possibilities of combining features from each of the last two designs are illustrated, and the advantages of adopting a more flexible and clinically relevant approach to the design of clinical trials are discussed.