American Statistical Association New York City Metropolitan Area Chapter New York State Psychiatric Institute at Columbia University Medical Center Biostatistics Seminar

Randomized controlled trials (RCTs) are preferred for causal inference. However, RCTs cannot be implemented to answer a number of important public health questions (e.g., effects of Hurricane Katrina or secondhand tobacco smoke on health outcomes). Two approaches, Rubin's potential outcomes from statistics and Campbell's pattern matching from the behavioral sciences, offer strong foundations for causal inference even in studies in which randomization is not possible or has been compromised. These approaches are applied to quantitative assignment designs (e.g., participants are assigned to treatment on the basis of need, merit, or risk) and designs in which the participants are assigned to treatment on the basis of unknown rules. These approaches can lead to relatively strong causal inferences, particularly if complementary design features are combined to strengthen. Empirical comparisons suggesting that alternative approaches produce similar effect size estimates to those of the RCT are described. Alternative designs permit a wider range of research questions to be answered and often permit more direct generalization of causal effects to practice; however, estimates of the magnitude of the causal effect may be more uncertain.

Stephen G. West is currently Professor of Psychology and he has also served as an investigator (methodologist) in the National Institute of Mental Health funded Preventive Intervention Research Center and in the National Institute of Aging funded Alzheimer's Disease Research Center at Arizona State University. He received his Ph.D. at the University of Texas at Austin. Dr. West is currently associate editor of Multivariate Behavioral Research, is past editor of Psychological Methods, is past editor of Journal of Personality, and past associate editor of Evaluation Review. He is also the co-author or co-editor of 12 books and edited volumes. He is a fellow of Divisions 5 (evaluation, measurement, and statistics) and 27 (society for community research and action) of the American Psychological Association.

Dr. West’s primary quantitative research interests are in the design and statistical analysis of field research, multiple regression, structural equation modeling, and longitudinal data analysis. His substantive research interests are in the design and evaluation of preventive interventions in health and mental health, and in personality psychology, particularly the consistency and coherence of behavior over time and situation.