title: COS-STAR: a reporting guideline for studies developing core outcome sets (protocol).
abstract: BACKGROUND
  Core outcome sets can increase the efficiency and value of research and, as a result, there are an increasing number of studies looking to develop core outcome sets (COS). However, the credibility of a COS depends on both the use of sound methodology in its development and clear and transparent reporting of the processes adopted. To date there is no reporting guideline for reporting COS studies. The aim of this programme of research is to develop a reporting guideline for studies developing COS and to highlight some of the important methodological considerations in the process.
  
  
  METHODS
  The study will include a reporting guideline item generation stage which will then be used in a Delphi study. The Delphi study is anticipated to include two rounds. The first round will ask stakeholders to score the items listed and to add any new items they think are relevant. In the second round of the process, participants will be shown the distribution of scores for all stakeholder groups separately and asked to re-score. A final consensus meeting will be held with an expert panel and stakeholder representatives to review the guideline item list. Following the consensus meeting, a reporting guideline will be drafted and review and testing will be undertaken until the guideline is finalised. The final outcome will be the COS-STAR (Core Outcome Set-STAndards for Reporting) guideline for studies developing COS and a supporting explanatory document.
  
  
  CONCLUSIONS
  To assess the credibility and usefulness of a COS, readers of a COS development report need complete, clear and transparent information on its methodology and proposed core set of outcomes. The COS-STAR guideline will potentially benefit all stakeholders in COS development: COS developers, COS users, e.g. trialists and systematic reviewers, journal editors, policy-makers and patient groups.
authors: Department of Biostatistics, University of Liverpool, Liverpool, UK. jjk@liv.ac.uk.
authors: Jamie J
authors: JJ
authors: Kirkham
authors: Department of Biostatistics, University of Liverpool, Liverpool, UK. sgorst@liverpool.ac.uk.
authors: Sarah
authors: S
authors: Gorst
authors: Centre for Statistics in Medicine, University of Oxford, Oxford, UK. doug.altman@csm.ox.ac.uk.
authors: Douglas G
authors: DG
authors: Altman
authors: School of Social & Community Medicine, University of Bristol, Bristol, UK. J.M.Blazeby@bristol.ac.uk.
authors: Jane
authors: J
authors: Blazeby
authors: Centre for Public Health, Queen's University Belfast, Belfast, UK. m.clarke@qub.ac.uk.
authors: Mike
authors: M
authors: Clarke
authors: National University of Ireland Galway & West Northwest Hospitals Group, Galway, Ireland. declan.devane@nuigalway.ie.
authors: Declan
authors: D
authors: Devane
authors: Department of Biostatistics, University of Liverpool, Liverpool, UK. gargon01@liverpool.ac.uk.
authors: Elizabeth
authors: E
authors: Gargon
authors: Department of Biostatistics, University of Liverpool, Liverpool, UK. prw@liv.ac.uk.
authors: Paula R
authors: PR
authors: Williamson
mesh_terms: D057189:Checklist; D002986:Clinical Trials as Topic / Q000592:standards*; D032921:Consensus; D003245:Consensus Statements as Topic; D003697:Delphi Technique; D023381:Endpoint Determination / Q000592:standards*; D006801:Humans; D017410:Practice Guidelines as Topic / Q000592:standards*; D012107:Research Design / Q000592:standards*; D016896:Treatment Outcome