Reducing the risk of bias in health behaviour change trials: Improving trial design, reporting or bias assessment criteria? A review and case study

Marijn de Bruin*, Jim McCambridge, Jan M. Prins

*Corresponding author for this work

Research output: Contribution to journalArticle

25 Citations (Scopus)


Objective: It has been suggested that randomised controlled trials (RCTs) of health behaviour change (HBC) interventions are less rigorously designed than - for example- drug trials. This study presents an approach to clarifying whether this is due to poor trial design, incomplete trial reporting and/or the inappropriateness of commonly applied risk of bias assessment criteria.

Design: First, a framework of key sources of bias and common strategies for reducing bias risk is developed based on a literature review. Second, we describe the design of a multi-site RCT evaluating the cost-effectiveness of an HIV-treatment adherence intervention (case study). The choices made by the multidisciplinary team trying to minimise the risk of bias are compared against the risk of bias framework.

Main outcome measures: Implementation of common strategies for reducing the risk of bias in the case study; alternative or additional strategies applied; a justification for each deviation from the risk of bias framework.

Results: Most of the common strategies for reducing the risk of bias could be implemented. Alternative strategies were developed for minimising the risk of performance bias and contamination. Several additional, domain-specific risk of bias strategies were implemented.

Conclusions: The literature provides useful guidance for reducing the risk of bias in HBC trials. Yet, the case study suggests that HBC trial designers may face specific challenges that require alternative/additional measures for reducing the risk of bias. Using the risk of bias justification table (RATIONALE) could lead to better-designed HBC trials, more comprehensive trial reports and the data necessary for evaluating the appropriateness of commonly applied risk of bias assessment criteria to HBC trials.

Original languageEnglish
Pages (from-to)8-34
Number of pages27
JournalPsychology & Health
Issue number1
Early online date21 Oct 2014
Publication statusPublished - 2 Jan 2015



  • methodology
  • randomised controlled trial
  • risk of bias
  • intervention
  • Cochrane
  • behaviour change
  • randomized-controlled-trials
  • active antiretroviral therapy
  • clinical-trials
  • HIV-1-infected patients
  • interventions
  • adherence
  • outcomes
  • care
  • contamination
  • medication

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