The selection and design of control conditions for randomized controlled trials of psychological interventions

UMMS Affiliation

Department of Medicine, Division of Preventive and Behavioral Medicine

Publication Date


Document Type



Evidence-Based Medicine; Humans; Mental Disorders; Randomized Controlled Trials as Topic; *Research Design


Life Sciences | Medicine and Health Sciences | Women's Studies


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.

DOI of Published Version



Psychother Psychosom. 2009;78(5):275-84. Epub 2009 Jul 11. Link to article on publisher's site

Journal/Book/Conference Title

Psychotherapy and psychosomatics

Related Resources

Link to Article in PubMed

PubMed ID