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This article was a joint collaboration with the members of the trial attrition study group: Stephen D. Brealey, Jo C. Dumville, Elaine M. Hay, Catherine E. Hewitt, Jennifer A. Klaber Moffett, Bharathy Kumaravel, Hugh MacPherson, Elaine Thomas, David J. Torgerson, and Jude Watson.
Contributors: J.C.D. had the idea of studying the impact of attrition in a sample of randomized controlled trials (RCTs). B.K. carried out the analysis under the guidance of C.E.H., D.J.T., and J.C.D. D.J.T. is the director of the York Trials Unit and identified trials for this study. The study used a convenience sample of 10 RCTs of musculoskeletal trials for which we obtained permission to use the individual patient data. E.M.H., J.A.K.M., H.MacP., S.D.B., J.W., and D.J.T. contributed data to the study. The authors wrote the article and the trial attrition study group critically reviewed versions of the manuscript. C.E.H. is the guarantor.
Funding: No additional funding.
Competing interests: None declared.
Provenance and peer review: Not commissioned; peer reviewed by the trial attrition study group.