Core Outcome Measures in Effectiveness Trials

COMET Initiative

The COMET (Core Outcome Measures in Effectiveness Trials) Initiative brings together people interested in the development and application of agreed standardised sets of outcomes, known as ‘core outcome sets’ (COS). These sets represent the minimum that should be measured and reported in all clinical trials of a specific condition, and are also suitable for use in clinical audit or research other than randomised trials. The existence or use of a core outcome set does not imply that outcomes in a particular trial should be restricted to those in the relevant core outcome set. Rather, there is an expectation that the core outcomes will be collected and reported, making it easier for the results of trials to be compared, contrasted and combined as appropriate; while researchers continue to explore other outcomes as well. COMET aims to collate and stimulate relevant resources, both applied and methodological, to facilitate exchange of ideas and information, and to foster methodological research in this area. The COMET Handbook Version 1.0 is available here.

When searching the COMET database, please note that a systematic review is currently underway to identify eligible material, and we are continually updating the database as we identify eligible studies. Therefore, the records retrieved by any search might increase on a daily basis.

The COMET database currently contains 1010 references of planned, ongoing and completed work.

The keyword used for the search will be compared with study title, abstract and author's surname.

View full search options

To view a demonstration of how to search the COMET database click here

Core resource pack

Useful references for core outcome set developers.

This includes an overview of the problems with outcomes in trials, key issues to consider in the development of a core outcome set, examples of core outcome set development, and things to think about once a COS is agreed. To read more, click here.

Latest News

  • Tuesday 13 March, 2018 - Exploring patient and public experience of involvement in the design of COS studies

    Lucy, a PhD student at the University of Liverpool, is interviewing patients and members of the public who have inputted or advised on the design, planning and/or running of a COS study.

    If your COS study is completed or close to completion, could you help Lucy access interviewees? If so, please get in touch with Lucy by emailing or giving her a call on +44 (0)151 794 9964.

    Many thanks in advance.

  • Thursday 01 March, 2018 - Interpretation of the COMET Handbook (version 1.0) and its insight for developing core outcome sets in clinical trials of traditional Chinese medicine Chinese

    This paper interprets the COMET Handbook (version 1.0) and analyses its insight on the  construction of traditional Chinese medicine clinical research  COS, combined with the characteristics of traditional Chinese medicine clinical research, to provide a reference
    for related researchers.This paper has also been translated ino English. Both versions are now available on the COMET website Resources page.

  • Monday 19 February, 2018 - An updated systematic review of COS

    The COMET (Core Outcome Measures in Effectiveness Trials) Initiative maintains an up to date, publicly accessible online database of published and ongoing COS. An annual systematic review update is an important part of this process. This review employed the same, multifaceted approach that was used in the original review and the previous two updates.

    Eighteen publications, relating to 15 new studies describing the development of 15 COS, were eligible for inclusion in the review. Results show an increase in the use of mixed methods, including Delphi surveys. Clinical experts remain the most common stakeholder group involved. Overall, only 16% of the 259 COS studies published up to the end of 2016 have included participants from LMICs.

Recently Added Studies

  • Multi-morbidity risk assessment and prevention in adolescents and adults with cerebral palsy: establishing a core outcome set for clinical practice

    [View details]
  • Development of a core outcome measurement set for clinical trials in whiplash associated disorders (WAD)

    [View details]
  • Establishing a core endpoints set for studies examining treatments for opioid use disorder

    [View details]
  • Developing a core outcome set for studies on women with invasive placentation

    [View details]
  • Defining and evaluating novel procedures for involving patients in Core Outcome Set research: creating a meaningful long list of candidate outcome domains

    [View details]

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