The Selection and Design of Control Conditions for Randomized Controlled Trials of Psychological Interventions

• Published in: Psychotherapy and psychosomatics Vol. 78; no. 5; pp. 275 - 284
• Main Authors: Mohr, David C., Spring, Bonnie, Freedland, Kenneth E., Beckner, Victoria, Arean, Patricia, Hollon, Steven D., Ockene, Judith, Kaplan, Robert
• Format: Journal Article
• Language: English
• Published: Basel, Switzerland S. Karger AG 01.01.2009; Karger
• Subjects: Biological and medical sciences; Evidence-Based Medicine - methods; Humans; Medical sciences; Mental Disorders - psychology; Mental Disorders - therapy; Methodology. Experimentation; Psychology. Psychoanalysis. Psychiatry; Psychopathology. Psychiatry; Randomized Controlled Trials as Topic - methods; Research Design; Special Article; Techniques and methods; Randomized controlled trial, methodology; Psychological interventions; Randomized controlled trial, control conditions; Human; Evaluation; Methodology; Evidence-based practice; Psychotherapy; Controlled therapeutic trial; Review; Randomized controlled trial; Recommendation; control conditions; Treatment; Experimental design; Critical study
• ISSN: 0033-3190; 1423-0348
• DOI: 10.1159/000228248

The randomized controlled trial (RCT) provides critical support for evidence-based practice using psychological interventions. The control condition is the principal method of removing the influence of unwanted variables in RCTs. There is little agreement or consistency in the design and construction of control conditions. Because control conditions have variable effects, the results of RCTs can depend as much on control condition selection as on the experimental intervention. The aim of this paper is to present a framework for the selection and design of control conditions for these trials. Threats to internal validity arising from modern RCT methodology are reviewed and reconsidered. The strengths and weaknesses of several categories of control conditions are examined, including the ones that are under experimental control, the ones that are under the control of clinical service providers, and no-treatment controls. Considerations in the selection of control conditions are discussed and several recommendations are proposed. The aim of this paper is to begin to define principles by which control conditions can be selected or developed in a manner that can assist both investigators and grant reviewers.