Core Outcome Measures in Effectiveness Trials

Plain Language Summary

The COMET Initiative recognises the expertise and crucial contribution of patients and carers in developing relevant core outcome sets.

We have developed two plain language summaries:

  • The Core Outcome Set / COMET plain language summary explains what outcomes are and the problems with using different outcomes in research. It also explains what core outcomes sets are, including how they are developed, and it sets out what the COMET Initiative is trying to achieve. You can download the Summary here.
  • The Delphi Process plain language summary explains what outcomes and consensus processes are and what happens in a Delphi process. You can download the Summary here.


We have also developed a whiteboard animation video:

"What are Core Outcome Sets?" (A COMET Initiative video developed with patients & the public)



This video explains what core outcome sets (COS) are, why they are important and how patients and the public are involved in developing COS.

We acknowledge the involvement of the COS Video Development Group, including: Rosemary Humphreys; Christine Vial; Rebecca Craven; Nicola Harman; Liz Gargon; Bridget Young; Paula Williamson; Sarah Gorst and Heather Bagley.

If you are a COS developer and you decide to use this video in your COS study, we would be grateful if you could acknowledge the “What are Core Outcome Sets” COMET Initiative video.

For further information or comments, please contact Heather Bagley, COMET Patient and Public Involvement Coordinator,


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