Skip to content


  • Poster presentation
  • Open Access

Choosing outcomes for a core outcome set: does provision of feedback between delphi survey rounds help prioritise items?

  • 1, 4,
  • 1,
  • 1,
  • 2,
  • 1,
  • 1,
  • 1,
  • 1 and
  • 1, 3
Trials201516 (Suppl 2) :P57

  • Published:


  • Public Health
  • Obesity
  • Systematic Review
  • Initial Response
  • Qualitative Interview


A core outcome set (COS) is a minimal set of outcomes to be reported in a trial. Development is often challenging because patients and clinicians identify many important outcomes and prioritisation is difficult. Delphi surveys (with several rounds) are one approach for prioritising outcomes. Summarised participant responses are provided in subsequent ‘rounds’, allowing initial responses to be changed in light of this feedback. While developing a COS for obesity surgery, we explored the impact of this feedback on outcome prioritisation.


Systematic reviews and qualitative interviews with patients were undertaken to list all outcomes of obesity surgery. This was operationalised into a 130-item round 1 questionnaire, where participants rated each item on a 1 to 9 scale. Participants were expert clinicians and patients. Round 2 included the same 130 items, the individual's round 1 scores, and the patient and clinician median scores. Participants re-rated each item in light of this feedback. Items rated 8 or 9 by at least 70% of participants were considered ‘important’.


168 clinicians and 90 patients responded to round 1, and 76% and 90% of these responded to round 2, respectively. In round 1, 18 items were rated ‘important’ by clinicians and 25 by patients. In round 2, these numbers doubled to 36 items for clinicians and 49 for patients.


In this study, providing feedback did not result in increased prioritisation, but seemed to encourage participants to score more items highly. Further work is needed to understand how participants rate items in light of feedback.

Authors’ Affiliations

University of Bristol, Bristol, UK
University of Southampton, Southampton, UK
University Hospitals Bristol NHS Trust, Bristol, UK
Taunton and Somerset NHS Trust, Taunton, UK


© Coulman et al. 2015

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver ( applies to the data made available in this article, unless otherwise stated.


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate. Please note that comments may be removed without notice if they are flagged by another user or do not comply with our community guidelines.