Although efficacy and effectiveness studies are both important when evaluating interventions, they serve distinct purposes and have different study designs. Unfortunately, the distinction between these two types of trials is often poorly understood. In this primer, we highlight several differences between these two types of trials including study design, patient populations, intervention design, data analysis, and result reporting.
1Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
2Department of Clinical Sciences, University of Texas Southwestern, Dallas, Texas, USA
3Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
4Veterans Affairs Center for Clinical Management Research, Ann Arbor, Michigan, USA
*Correspondence: Amit G. Singal, MD, MS, Dedman Scholar of Clinical Care, Division of Digestive and Liver Diseases, University of Texas Southwestern Medical Center, 5959 Harry Hines Blvd, POB 1, Suite 420, Dallas, Texas 75390-8887, USA. E-mail: amit.singal@utsouthwestern.edu
Received 19 June 2013; accepted 19 August 2013
published online 2 January 2014
