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Cluster randomised trials in the medical literature: two bibliometric surveys

Bland, J.M. (orcid.org/0000-0002-9525-5334) (2004) Cluster randomised trials in the medical literature: two bibliometric surveys. BMC Medical Research Methodology. ISSN 1471-2288

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Background: Several reviews of published cluster randomised trials have reported that about half did not take clustering into account in the analysis, which was thus incorrect and potentially misleading. In this paper I ask whether cluster randomised trials are increasing in both number and quality of reporting. Methods: Computer search for papers on cluster randomised trials since 1980, hand search of trial reports published in selected volumes of the British Medical Journal over 20 years. Results: There has been a large increase in the numbers of methodological papers and of trial reports using the term 'cluster random' in recent years, with about equal numbers of each type of paper. The British Medical Journal contained more such reports than any other journal. In this journal there was a corresponding increase over time in the number of trials where subjects were randomised in clusters. In 2003 all reports showed awareness of the need to allow for clustering in the analysis. In 1993 and before clustering was ignored in most such trials. Conclusion: Cluster trials are becoming more frequent and reporting is of higher quality. Perhaps statistician pressure works.

Item Type: Article
Copyright, Publisher and Additional Information: © 2004 Bland; licensee BioMed Central Ltd. This is an open-access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Institution: The University of York
Academic Units: The University of York > Health Sciences (York)
Depositing User: Repository Officer
Date Deposited: 17 Feb 2006
Last Modified: 07 Aug 2016 00:03
Published Version: http://dx.doi.org/10.1186/1471-2288-4-21
Status: Published
Refereed: Yes
URI: http://eprints.whiterose.ac.uk/id/eprint/1033

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