Research article

BMC Medical Research Methodology

, 12:101

First online:

Open Access This content is freely available online to anyone, anywhere at any time.

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 SelbyAffiliated withAddictions Program, Centre for Addiction and Mental HealthDepartments of Family and Community Medicine and Psychiatry and the Dalla Lana School of Public Health, University of TorontoOntario Tobacco Research Unit Email author 
  • , Gerald BroskyAffiliated withDepartment of Family Medicine, Dalhousie University
  • , Paul I OhAffiliated withCardiac Rehabilitation and Secondary Prevention Program, Toronto Rehabilitation InstituteDepartment of Medicine, University of Toronto
  • , Vincent RaymondAffiliated withHealth Economics & Outcomes Research, Pfizer Canada Inc
  • , Suzanne RangerAffiliated withTherapeutic Areas, Cardiovascular and Respiratory, Medical Division, Pfizer Canada Inc



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