Hostname: page-component-78c5997874-t5tsf Total loading time: 0 Render date: 2024-11-11T07:29:59.079Z Has data issue: false hasContentIssue false
  • English
  • Français

THE TYPICAL COCHRANE REVIEW

How Many Trials? How Many Participants?

Published online by Cambridge University Press:  23 December 2002

Susan Mallett  and
Mike Clarke
Susan Mallett
Affiliation:
NHS Research and Development Programme
Mike Clarke
Affiliation:
NHS Research and Development Programme
Get access Rights & Permissions [Opens in a new window]

Abstract

Objectives: To describe the number of trials and participants in a typical systematic review from The Cochrane Database of Systematic Reviews.

Methods: The number of trials in 1,000 Cochrane systematic reviews in issue 1, 2001 of The Cochrane Database of Systematic Reviews was counted for three categories of trial: included trials, ongoing trials, and trials awaiting assessment for inclusion. (The term trial is used in this paper, although a small number of Cochrane reviews include studies that are not trials.) The total number of participants in included trials was extracted from a sample of reviews.

Results: A total of 9,778 trials were included in the Cochrane reviews. There were a further 356 ongoing trials and 1,138 trials awaiting assessment for inclusion. A typical review contained six included trials. Forty percent of the reviews listed ongoing trials and/or trials awaiting assessment for inclusion. Based on a sample of 258 reviews, the median number of participants per review was 945 (interquartile range, 313 to 2,511) per review and 118 (interquartile range, 60 to 241) per trial.

Conclusion: This report is a descriptive study of the number of trials and participants in a typical Cochrane review from The Cochrane Library, issue 1, 2001.

Keywords

Cochrane CollaborationSystematic reviewMeta-analysisRandomized trial
Type
RESEARCH NOTES
Information
International Journal of Technology Assessment in Health Care , Volume 18 , Issue 4 , December 2002 , pp. 820 - 823
Copyright
© 2002 Cambridge University Press

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)