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Developing core outcome sets for clinical trials: issues to consider

Paula R Williamson1*, Douglas G Altman2, Jane M Blazeby3, Mike Clarke4, Declan Devane5, Elizabeth Gargon1 and Peter Tugwell6

Author Affiliations

1 Department of Biostatistics, University of Liverpool, Shelley’s Cottage, Brownlow Street, Liverpool,, L69 3GS, UK

2 University of Oxford, Centre for Statistics in Medicine, Wolfson College Annexe, Linton Road, Oxford, OX2 6UD, UK

3 University of Bristol, School of Social and Community Medicine, 39 Whatley Road, Bristol, BS8 2PS, UK

4 Queens University Belfast, All-Ireland Hub for Trials Methodology Research, Institute of Clinical Sciences, Block B, Royal Victoria Hospital, Grosvenor Road, Belfast, BT12 6BJ, UK

5 National University of Ireland Galway, School of Nursing and Midwifery, University Road, Galway, Ireland

6 University of Ottawa, Institute of Population Health, 1 Stewart Street, Ottawa, ON, K1N 6N5, Canada

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Trials 2012, 13:132  doi:10.1186/1745-6215-13-132

Published: 6 August 2012


The selection of appropriate outcomes or domains is crucial when designing clinical trials in order to compare directly the effects of different interventions in ways that minimize bias. If the findings are to influence policy and practice then the chosen outcomes need to be relevant and important to key stakeholders including patients and the public, health care professionals and others making decisions about health care. There is a growing recognition that insufficient attention has been paid to the outcomes measured in clinical trials. These issues could be addressed through the development and use of an agreed standardized collection of outcomes, known as a core outcome set, which should be measured and reported, as a minimum, in all trials for a specific clinical area. Accumulating work in this area has identified the need for general guidance on the development of core outcome sets. Key issues to consider in the development of a core outcome set include its scope, the stakeholder groups to involve, choice of consensus method and the achievement of a consensus.

Core outcome set; Outcome reporting bias; Clinical trials; Systematic review; Methodology; Consensus