Randomized trials published in higher vs. lower impact journals differ in design, conduct, and analysis

Malgorzata M. Bala, Elie A. Akl, Xin Sun, Dirk Bassler, Dominik Mertz, Filip Mejza, Per Olav Vandvik, German Malaga, Bradley C. Johnston, Philipp Dahm, Pablo Alonso-Coello, Natalia Diaz-Granados, Sadeesh K. Srinathan, Basil Hassouneh, Matthias Briel, Jason W. Busse, John J. You, Stephen D. Walter, Douglas G. Altman, Gordon H. Guyatt

Research output: Contribution to journalArticlepeer-review

45 Scopus citations


Objective: To compare methodological characteristics of randomized controlled trials (RCTs) published in higher vs. lower impact Core Clinical Journals. Study Design and Setting: We searched MEDLINE for RCTs published in 2007 in Core Clinical Journals. We randomly sampled 1,140 study reports in a 1:1 ratio in higher (five general medicine journals with the highest total citations in 2007) and lower impact journals. Results: Four hundred sixty-nine RCTs proved eligible: 219 in higher and 250 in lower impact journals. RCTs in higher vs. lower impact journals had larger sample sizes (median, 285 vs. 39), were more likely to receive industry funding (53% vs. 28%), declare concealment of allocation (66% vs. 36%), declare blinding of health care providers (53% vs. 41%) and outcome adjudicators (72% vs. 54%), report a patient-important primary outcome (69% vs. 50%), report subgroup analyses (64% vs. 26%), prespecify subgroup hypotheses (42% vs. 20%), and report a test for interaction (54% vs. 27%); P < 0.05 for all differences. Conclusion: RCTs published in higher impact journals were more likely to report methodological safeguards against bias and patient-important outcomes than those published in lower impact journals. However, sufficient limitations remain such that publication in a higher impact journal does not ensure low risk of bias.

Original languageEnglish (US)
Pages (from-to)286-295
Number of pages10
JournalJournal of Clinical Epidemiology
Issue number3
StatePublished - Mar 2013

Bibliographical note

Funding Information:
Funding/support: M.B. is supported by santésuisse and the Gottfried and Julia Bangerter-Rhyner Foundation . J.W.B is funded by a New Investigator Award from the Canadian Institutes of Health Research and the Canadian Chiropractic Research Foundation . D.B. is supported by the European Union ( grant award health-F5-2009-223060 ). D.M. is supported by a research scholarship from the Swiss National Science Foundation ( PBBSP3-124436 and PASMP3-132571 ) and Lichtenstein-Stiftung , Basel, Switzerland. P.D. is supported by a Dennis W. Jahnigan Carreer Development Award by the American Geriatrics Society . S.K.S. holds a Rudy Falk Clinician Scientist Award. P.A.-C. is funded by a Miguel Servet research contract from the Instituto de Salud Carlos III ( CP09/00137 ). J.J.Y. is supported by a Hamilton Health Sciences Early Career Award.

Copyright 2013 Elsevier B.V., All rights reserved.


  • Data interpretation
  • Humans
  • Periodical
  • Randomized controlled trial
  • Research design
  • Systematic review

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