title: Cluster-randomized trials: A closer look.
abstract: The cluster-randomized trial is the methodology of choice for evaluating interventions administered at the group level such as public health and healthcare quality improvement interventions. Because of unique features of this design, it can be difficult to apply standard research ethics guidelines to cluster-randomized trials. The Ottawa Statement on the Ethical Design and Conduct of Cluster-Randomized Trials provides researchers and research ethics committees with comprehensive guidance on the ethical design, conduct and review of cluster-randomized trials. The Ottawa Statement supplements current national and international research ethics guidelines with guidance that is specific to cluster-randomized trials. In a recently published commentary, three examples drawn from the ClinicalTrials.gov registry were used to illustrate challenges associated with the cluster-randomized trial design. The commentary argued that the Ottawa Statement fails to provide comprehensive ethical guidance. In this article, we illustrate the application of the Ottawa Statement to the three trials. We challenge the conclusions reached in the commentary by demonstrating that an ethical analysis requires complete information. We correct some misperceptions about the cluster-randomized trial design.
  
  
  
  We collected essential additional information by contacting the authors of trials and by referring to published trial articles. We used the Ottawa Statement to conduct an ethical analysis of each trial and to address a number of substantive concerns raised regarding the identification of study participants, informed consent and harm benefit analysis.
  
  
  
  In the two cases in which we were able to obtain detailed study information, we were able to complete the ethical analysis prescribed by the Ottawa Statement.
  
  
  
  The Ottawa Statement does provide a useful framework for the ethical design, review and conduct of cluster-randomized trials.
authors.affiliation: Department of Emergency Medicine, Foothills Medical Centre, University of Calgary, Calgary, AB, Canada Rotman Institute of Philosophy, Western University, London, ON, Canada amcrae@ucalgary.ca.
authors.forename: Andrew D
authors.initials: AD
authors.lastname: McRae
authors.affiliation: Rotman Institute of Philosophy, Western University, London, ON, Canada Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada Department of Epidemiology and Community Medicine, University of Ottawa, Ottawa, ON, Canada.
authors.forename: Monica
authors.initials: M
authors.lastname: Taljaard
authors.affiliation: Rotman Institute of Philosophy, Western University, London, ON, Canada Department of Medicine, University of Western Ontario, London, ON, Canada Department of Epidemiology and Biostatistics, University of Western Ontario, London, ON, Canada.
authors.forename: Charles
authors.initials: C
authors.lastname: Weijer
mesh_terms: D000925:Anticoagulants / Q000008:administration & dosage; D019468:Disease Management; D028744:Ethics Committees, Research; D032984:Ethics, Research; D005193:Family Planning Services; D017408:Guidelines as Topic; D015658:HIV Infections / Q000628:therapy; D006296:Health Services; D006801:Humans; D007258:Informed Consent; D008288:Malaria / Q000175:diagnosis; D016032:Randomized Controlled Trials as Topic / Q000941:ethics*; D012042:Registries; D012107:Research Design; D018570:Risk Assessment; D014859:Warfarin / Q000008:administration & dosage
chemical_list: D000925:Anticoagulants; D014859:Warfarin
keywords: Cluster-randomized trials; harm benefit analysis; informed consent; the Ottawa Statement