Alternatives to the randomized controlled trial.
Public health researchers are addressing new research questions (e.g., effects of environmental tobacco smoke, Hurricane Katrina) for which the randomized controlled 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.
Psychology Department, Arizona State University, Tempe, AZ 85287-1104, USA. sgwest@asu.edu
Stephen G
SG
West
Naihua
N
Duan
Willo
W
Pequegnat
Paul
P
Gaist
Don C
DC
Des Jarlais
David
D
Holtgrave
José
J
Szapocznik
Martin
M
Fishbein
Bruce
B
Rapkin
Michael
M
Clatts
Patricia Dolan
PD
Mullen
D015984:Causality; D002755:Choice Behavior; D015340:Epidemiologic Research Design; D006801:Humans; D011634:Public Health; D036301:Qualitative Research; D016032:Randomized Controlled Trials as Topic; D012044:Regression Analysis; D015203:Reproducibility of Results; D035842:Research Subjects / Q000523:psychology