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The quality of reports of randomised trials in 2000 and 2006: comparative study of articles indexed in PubMed

BMJ 2010; 340 doi: (Published 24 March 2010) Cite this as: BMJ 2010;340:c723
  1. Sally Hopewell, senior research fellow1,
  2. Susan Dutton, senior medical statistician1,
  3. Ly-Mee Yu, senior medical statistician1,
  4. An-Wen Chan, assistant professor2,
  5. Douglas G Altman, director 1
  1. 1Centre for Statistics in Medicine, University of Oxford, Linton Road, Oxford OX2 6UD
  2. 2Women’s College Research Institute, Department of Medicine, University of Toronto, ON M5S 1B2, Canada
  1. Correspondence to: S Hopewell sally.hopewell{at}
  • Accepted 25 January 2010


Objectives To examine the reporting characteristics and methodological details of randomised trials indexed in PubMed in 2000 and 2006 and assess whether the quality of reporting has improved after publication of the Consolidated Standards of Reporting Trials (CONSORT) Statement in 2001.

Design Comparison of two cross sectional investigations.

Study sample All primary reports of randomised trials indexed in PubMed in December 2000 (n=519) and December 2006 (n=616), including parallel group, crossover, cluster, factorial, and split body study designs.

Main outcome measures The proportion of general and methodological items reported, stratified by year and study design. Risk ratios with 95% confidence intervals were calculated to represent changes in reporting between 2000 and 2006.

Results The majority of trials were two arm (379/519 (73%) in 2000 v 468/616 (76%) in 2006) parallel group studies (383/519 (74%) v 477/616 (78%)) published in specialty journals (482/519 (93%) v 555/616 (90%)). In both 2000 and 2006, a median of 80 participants were recruited per trial for parallel group trials. The proportion of articles that reported drug trials decreased between 2000 and 2006 (from 393/519 (76%) to 356/616 (58%)), whereas the proportion of surgery trials increased (51/519 (10%) v 128/616 (21%)). There was an increase between 2000 and 2006 in the proportion of trial reports that included details of the primary outcome (risk ratio (RR) 1.18, 95% CI 1.04 to 1.33), sample size calculation (RR 1.66, 95% CI 1.40 to 1.95), and the methods of random sequence generation (RR 1.62, 95% CI 1.32 to 1.97) and allocation concealment (RR 1.40, 95% CI 1.11 to 1.76). There was no difference in the proportion of trials that provided specific details on who was blinded (RR 0.91, 95% CI 0.75 to 1.10).

Conclusions Reporting of several important aspects of trial methods improved between 2000 and 2006; however, the quality of reporting remains well below an acceptable level. Without complete and transparent reporting of how a trial was designed and conducted, it is difficult for readers to assess its conduct and validity.


  • We are grateful to Sophie Moher and Sui Yan Wong for their help in reviewing articles and assessing journal instructions to authors.

  • Contributors: SH was involved in the design, implementation, and analysis of the study, and in writing, and commenting on, drafts on the final manuscript. SD, L-MY, A-WC, and DGA were involved in the design, implementation, and analysis of the study, and commented on drafts on the final manuscript. SH is the guarantor of the study.

  • Funding: This study was carried out as part of a larger study funded by a grant from the UK National Institute for Health Research to support the work of the CONSORT Group. The funder had no role in the design, analysis, or interpretation of the study, or in writing of the manuscript.

  • Competing interests: All authors have completed the Unified Competing Interest form at (available on request from the corresponding author) and declare (1) No financial support for the submitted work from anyone other than their employer; (2) No financial relationships with commercial entities that might have an interest in the submitted work; (3) No spouses, partners, or children with relationships with commercial entities that might have an interest in the submitted work; (4) No non-financial interests that may be relevant to the submitted work. DGA is a member of the CONSORT executive group and SH works as a CONSORT senior research fellow.

  • Data sharing: Data set available on request from the corresponding author at sally.hopewell{at}

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