How to select outcome measurement instruments for outcomes included in a "Core Outcome Set" - a practical guideline.
In cooperation with the Core Outcome Measures in Effectiveness Trials (COMET) initiative, the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) initiative aimed to develop a guideline on how to select outcome measurement instruments for outcomes (i.e., constructs or domains) included in a "Core Outcome Set" (COS). A COS is an agreed minimum set of outcomes that should be measured and reported in all clinical trials of a specific disease or trial population.



Informed by a literature review to identify potentially relevant tasks on outcome measurement instrument selection, a Delphi study was performed among a panel of international experts, representing diverse stakeholders. In three consecutive rounds, panelists were asked to rate the importance of different tasks in the selection of outcome measurement instruments, to justify their choices, and to add other relevant tasks. Consensus was defined as being achieved when 70 % or more of the panelists agreed and when fewer than 15 % of the panelists disagreed.



Of the 481 invited experts, 120 agreed to participate of whom 95 (79 %) completed the first Delphi questionnaire. We reached consensus on four main steps in the selection of outcome measurement instruments for COS: Step 1, conceptual considerations; Step 2, finding existing outcome measurement instruments, by means of a systematic review and/or a literature search; Step 3, quality assessment of outcome measurement instruments, by means of the evaluation of the measurement properties and feasibility aspects of outcome measurement instruments; and Step 4, generic recommendations on the selection of outcome measurement instruments for outcomes included in a COS (consensus ranged from 70 to 99 %).



This study resulted in a consensus-based guideline on the methods for selecting outcome measurement instruments for outcomes included in a COS. This guideline can be used by COS developers in defining how to measure core outcomes.
Department of Epidemiology and Biostatistics, EMGO Institute for Health and Care Research, VU University Medical Center, De Boelelaan 1089a, 1081 HV, Amsterdam, The Netherlands. c.prinsen@vumc.nl.
Cecilia A C
CA
Prinsen
Department of Pediatrics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada.|School of Public Health, University of Alberta, Edmonton, AB, Canada.|Women's and Children's Health Research Institute, University of Alberta, Edmonton, AB, Canada.
Sunita
S
Vohra
Department of Neurology, King's College Hospital, London, UK.
Michael R
MR
Rose
Department of Epidemiology and Biostatistics, EMGO Institute for Health and Care Research, VU University Medical Center, De Boelelaan 1089a, 1081 HV, Amsterdam, The Netherlands.|Amsterdam Rheumatology & Immunology Center, Amsterdam, The Netherlands.
Maarten
M
Boers
Department of Medicine, University of Ottawa, Ottawa, ON, Canada.
Peter
P
Tugwell
Northern Ireland Network for Trials Methodology Research, Institute of Clinical Sciences, Royal Hospitals, Queen's University Belfast, Belfast, UK.
Mike
M
Clarke
Department of Biostatistics, University of Liverpool, Liverpool, UK.
Paula R
PR
Williamson
Department of Epidemiology and Biostatistics, EMGO Institute for Health and Care Research, VU University Medical Center, De Boelelaan 1089a, 1081 HV, Amsterdam, The Netherlands.
Caroline B
CB
Terwee
D003697:Delphi Technique; D006801:Humans; D017063:Outcome Assessment, Health Care; D017410:Practice Guidelines as Topic
COMET; COSMIN; Core Outcome Set; Delphi study; Guideline; Instrument selection; Outcome measurement instrument; Outcomes research