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Open Access Research article

How pragmatic or explanatory is the randomized, controlled trial? The application and enhancement of the PRECIS tool to the evaluation of a smoking cessation trial

Peter Selby123*, Gerald Brosky4, Paul I Oh56, Vincent Raymond7 and Suzanne Ranger8

Author Affiliations

1 Addictions Program, Centre for Addiction and Mental Health, 100 Stokes St., 33 Russell Street, Toronto, ON M6J 1H4, Canada

2 Departments of Family and Community Medicine and Psychiatry and the Dalla Lana School of Public Health, University of Toronto, Toronto, ON Canada

3 Ontario Tobacco Research Unit, Toronto, ON Canada

4 Department of Family Medicine, Dalhousie University, Halifax, NS, Canada

5 Cardiac Rehabilitation and Secondary Prevention Program, Toronto Rehabilitation Institute, Toronto, ON Canada

6 Department of Medicine, University of Toronto, Toronto, ON Canada

7 Health Economics & Outcomes Research, Pfizer Canada Inc, Kirkland, Québec, Canada

8 Therapeutic Areas, Cardiovascular and Respiratory, Medical Division, Pfizer Canada Inc, Kirkland, Québec, Canada

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BMC Medical Research Methodology 2012, 12:101  doi:10.1186/1471-2288-12-101

Published: 23 July 2012



Numerous explanatory randomized trials support the efficacy of chronic disease interventions, including smoking cessation treatments. However, there is often inadequate adoption of these interventions for various reasons, one being the limitation of generalizability of the explanatory studies in real-world settings. Randomized controlled trials can be rated as more explanatory versus pragmatic along 10 dimensions. Pragmatic randomized clinical trials generate more realistic estimates of effectiveness with greater relevance to clinical practice and for health resource allocation decisions. However, there is no clear method to scale each dimension during the trial design phase to ensure that the design matches the intended purpose of the study.


We designed a pragmatic, randomized, controlled study to maximize external validity by addressing several barriers to smoking cessation therapy in ambulatory care. We analyzed our design and methods using the recently published ‘Pragmatic–Explanatory Continuum Indicatory Summary (PRECIS)’ tool, a qualitative method to assess trial design across 10 domains. We added a 20-point numerical rating scale and a modified Delphi process to improve consensus in rating these domains.


After two rounds of review, there was consensus on all 10 domains of study design. No single domain was scored as either fully pragmatic or fully explanatory; but overall, the study scored high on pragmatism.


This addition to the PRECIS tool may assist other trial designers working with interdisciplinary co-investigators to rate their study design while building consensus.

Clinical trial; Explanatory; Pragmatic; Smoking cessation; PRECIS; Varenicline; Bupropion; Nicotine replacement therapy