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Variability in research ethics review of cluster randomized trials: a scenario-based survey in three countries

Monica Taljaard11423*, Jamie C Brehaut12, Charles Weijer356, Robert Boruch7, Allan Donner368, Martin P Eccles9, Andrew D McRae103, Raphael Saginur114, Merrick Zwarenstein12 and Jeremy M Grimshaw13234

Author Affiliations

1 Ottawa Hospital Research Institute, Clinical Epidemiology Program, 1053 Carling Avenue, Civic Campus, C409, Ottawa, ON K1Y 4E9, Canada

2 Department of Epidemiology and Community Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON K1H 8M5, Canada

3 Rotman Institute of Philosophy, Department of Philosophy, Stevenson Hall 2150, Western University, London, ON N6A 5B8, Canada

4 Department of Medicine, University of Ottawa, Ottawa, ON Canada

5 Department of Medicine, Western University, London, ON Canada

6 Department of Epidemiology and Biostatistics, Western University, Kresge Building, Room K201, London, ON N6A 5C1, Canada

7 Graduate School of Education and Statistics Department, Wharton School, University of Pennsylvania, 3700 Walnut Street, Philadelphia, PA 19104, USA

8 Robarts Clinical Trials, Robartsca

9 Institute of Health & Society, Newcastle University, 21 Claremont Place, Newcastle upon Tyne NE2 4AA, UK

10 Department of Emergency Medicine, University of Calgary, Foothills Medical Centre, Calgary, AB Canada

11 Division of Infectious Disease, Ottawa Hospital-Civic Campus, 1053 Carling Avenue, Ottawa, ON K1Y 4E9, Canada

12 Centre for Health Services Sciences, Sunnybrook Health Sciences Centre, 2075 Bayview Avenue, Toronto M4N 3 M5, Canada

13 Ottawa Hospital Research Institute, Clinical Epidemiology Program, The Ottawa Hospital - General Campus, 501 Smyth Road, Box 711, Ottawa, ON K1H 8 L6, Canada

14 Ottawa Hospital Research Institute, Clinical Epidemiology Program, Ottawa Hospital, Civic Campus, 1053 Carling Avenue, Civic Box 693, Admin Services Building, ASB 2–004, Ottawa, ON K1Y 4E9, USA

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Trials 2014, 15:48  doi:10.1186/1745-6215-15-48

Published: 5 February 2014



Cluster randomized trials (CRTs) present unique ethical challenges. In the absence of a uniform standard for their ethical design and conduct, problems such as variability in procedures and requirements by different research ethics committees will persist. We aimed to assess the need for ethics guidelines for CRTs among research ethics chairs internationally, investigate variability in procedures for research ethics review of CRTs within and among countries, and elicit research ethics chairs’ perspectives on specific ethical issues in CRTs, including the identification of research subjects. The proper identification of research subjects is a necessary requirement in the research ethics review process, to help ensure, on the one hand, that subjects are protected from harm and exploitation, and on the other, that reviews of CRTs are completed efficiently.


A web-based survey with closed- and open-ended questions was administered to research ethics chairs in Canada, the United States, and the United Kingdom. The survey presented three scenarios of CRTs involving cluster-level, professional-level, and individual-level interventions. For each scenario, a series of questions was posed with respect to the type of review required (full, expedited, or no review) and the identification of research subjects at cluster and individual levels.


A total of 189 (35%) of 542 chairs responded. Overall, 144 (84%, 95% CI 79 to 90%) agreed or strongly agreed that there is a need for ethics guidelines for CRTs and 158 (92%, 95% CI 88 to 96%) agreed or strongly agreed that research ethics committees could be better informed about distinct ethical issues surrounding CRTs. There was considerable variability among research ethics chairs with respect to the type of review required, as well as the identification of research subjects. The cluster-cluster and professional-cluster scenarios produced the most disagreement.


Research ethics committees identified a clear need for ethics guidelines for CRTs and education about distinct ethical issues in CRTs. There is disagreement among committees, even within the same countries, with respect to key questions in the ethics review of CRTs. This disagreement reflects variability of opinion and practices pointing toward possible gaps in knowledge, and supports the need for explicit guidelines for the ethical conduct and review of CRTs.

Cluster randomized trials; Informed consent; Research ethics guidelines; Research ethics review; Web-based survey