title: Protocol for developing, disseminating and implementing a core outcome set for endometriosis.
abstract: Endometriosis is a common gynaecological disease characterised by pain and subfertility. Randomised controlled trials evaluating treatments for endometriosis have reported many different outcomes and outcome measures. This variation restricts effective data synthesis limiting the usefulness of research to inform clinical practice. To address these methodological concerns, we aim to develop, disseminate and implement a core outcome set for endometriosis engaging with key stakeholders, including healthcare professionals, researchers and women with endometriosis.
  
  
  
  An international steering group has been established, including healthcare professionals, researchers and patient representatives. Potential outcomes identified from a systematic review of the literature will be entered into a modified Delphi method. Key stakeholders will be invited to participate including healthcare professionals, researchers and women with endometriosis. Participants will be invited to score individual outcomes on a nine-point Likert scale anchored between 1 (not important) and 9 (critical). Repeated reflection and rescoring should promote whole and individual stakeholder group converge towards consensus, 'core', outcomes. High-quality outcome measures will be associated with core outcomes.
  
  
  
  The implementation of a core outcome set for endometriosis within future clinical trials, systematic reviews and clinical guidelines will enhance the availability of comparable data to facilitate evidence-based patient care. This study was prospectively registered with Core Outcome Measures in Effectiveness Trials Initiative; number: 691.
authors.affiliation: Women's Health Research Unit, Barts and the London School of Medicine and Dentistry, London, UK.
authors.forename: Martin
authors.initials: M
authors.lastname: Hirsch
authors.affiliation: Balliol College, University of Oxford, Oxford, UK.
authors.forename: James M N
authors.initials: JM
authors.lastname: Duffy
authors.affiliation: Radcliffe Women's Health Patient Participation Group, University of Oxford, Oxford, UK.
authors.forename: Claire
authors.initials: C
authors.lastname: Barker
authors.affiliation: World Endometriosis Society, Vancouver, British Columbia, Canada.|World Endometriosis Research Foundation, London, UK.
authors.forename: Lone
authors.initials: L
authors.lastname: Hummelshoj
authors.affiliation: World Endometriosis Society, Vancouver, British Columbia, Canada.|Robinson Research Institute, University of Adelaide, Adelaide, South Australia, Australia.
authors.forename: Neil P
authors.initials: NP
authors.lastname: Johnson
authors.affiliation: Robinson Research Institute, University of Adelaide, Adelaide, South Australia, Australia.
authors.forename: Ben
authors.initials: B
authors.lastname: Mol
authors.affiliation: Women's Health Research Unit, Barts and the London School of Medicine and Dentistry, London, UK.
authors.forename: Khalid S
authors.initials: KS
authors.lastname: Khan
authors.affiliation: Cochrane Gynaecology and Fertility Group, University of Auckland, Auckland, New Zealand.
authors.forename: Cindy
authors.initials: C
authors.lastname: Farquhar
mesh_terms: D032921:Consensus; D003697:Delphi Technique; D004715:Endometriosis / Q000628:therapy*; D005260:Female; D006282:Health Personnel; D006801:Humans; D017063:Outcome Assessment, Health Care; D010361:Patients; D012107:Research Design; D012108:Research Personnel; D000073597:Stakeholder Participation; D057170:Translational Research, Biomedical
keywords: Consensus methodology; Core outcome sets; Endometriosis; Outcome variation; outcome harmonization