NIH: Office of Disease Prevention

Medicine: Mind the Gap

Strengths and Weaknesses of Experimental and Quasi-Experimental Designs

Tuesday, November 5, 2013
*This Mind the Gap lecture was presented as a webinar.

William R. Shadish, Ph.D. External Website Policy
Distinguished Professor and Founding Faculty
   Chair for Academic Personnel

Psychological Sciences Section
  School of Social Sciences, Humanities, and Arts
University of California, Merced


About the Seminar

Recent years have seen important advances in the design and analysis of both randomized experiments and quasi-experiments. A particular focus has been empirical tests of the conditions under which nonrandomized experiments can approximate answers from a randomized experiment. Such efforts have a long history in fields such as medicine (Gilbert, McPeek, and Mosteller, 1977), psychology (Smith and Glass, 1978), and economics (LaLonde, 1986). Recent work is prompted by such factors as evidence-based practice and theoretical advances such as Rubin's causal model.

This webinar reviewed illustrative studies that demonstrate the direction such work is taking and the results that seem to be emerging in regards to nonrandomized control group designs, regression discontinuity designs, and interrupted time series designs.

About William R. Shadish, Ph.D.

William R. Shadish, Ph.D. External Website Policy is Distinguished Professor and Founding Faculty, University of California, Merced. He received his bachelor's degree in sociology from Santa Clara University in 1972, and his M.S. (1975) and Ph.D. (1978) degrees from Purdue University in clinical psychology, with minor areas in statistics and measurement. He completed a postdoctoral fellowship in methodology and program evaluation at Northwestern University from 1978 to 1981. His current research interests include experimental and quasi-experimental design, the empirical study of methodological issues, and the methodology and practice of meta-analysis. He is author (with T.D. Cook and D.T. Campbell, 2002) of Experimental and Quasi-Experimental Designs for Generalized Causal Inference; (with T.D. Cook and L.C. Leviton, 1991) of Foundations of Program Evaluation; (with L. Robinson and C. Lu, 1997) of ES: A Computer Program and Manual for Effect Size Calculation. He is also co-editor of five other volumes and the author of over 165 articles and chapters. He was the founding Secretary-Treasurer of the Society for Research Synthesis Methodology (2005-2010) and is its 2013 President. He was 1997 President of the American Evaluation Association, winner of the 1994 Paul F. Lazarsfeld Award for Evaluation Theory from the American Evaluation Association, the 2000 Robert Ingle Award for service to the American Evaluation Association, the 1994 and 1996 Outstanding Research Publication Awards from the American Association for Marriage and Family Therapy, the 2002 Donald T. Campbell Award for Innovations in Methodology from the Policy Studies Organization, the 2009 Frederick Mosteller Award for Lifetime Contributions to Systematic Reviews from the Campbell Collaboration, and the 2011 Ingram Olkin Award for Lifetime Contributions to Systematic Reviews from the Society for Search Synthesis Methodology. He is a Fellow of the American Psychological Association, Associate Editor of American Psychologist, past Associate Editor of Multivariate Behavioral Research, and past Editor of New Directions for Evaluation.