Multi-Round compared to Real-Time Delphi for consensus in core outcome set (COS) development: a randomised trial

Background: The Delphi method is used in a wide variety of settings as a method of building consensus on important issues. Traditionally, the Delphi method uses multiple rounds of a survey to allow for feedback of other participants’ survey responses in between rounds. By informing participants about how others answer a question or prioritise specific topics, it allows for diverse opinions to inform the consensus process. For this reason, the Delphi method is popular as a consensus building approach in developing core outcome sets (COS), i.e. the minimum agreed set of standardised outcomes that should be measured and reported in studies on a specific health condition. In a COS setting, participants prioritise the importance of outcomes for inclusion in a COS. This usually involves participating in multiple rounds of a survey that can span several weeks or months. Challenges with participant retention have been highlighted in previous COS. We will compare a three-round with a Real-Time Delphi approach on prioritised outcomes. This trial is embedded within the COHESION study which is developing a COS for interventions treating neonatal encephalopathy. Methods: One hundred and eighty stakeholders (parents/caregivers of infants diagnosed and treated with neonatal encephalopathy, healthcare providers and researchers) will be randomised using stratified randomisation to take part in either the Multi-Round or Real-Time Delphi. Stakeholders will rate the importance of the same set of outcomes in both arms. We will compare the prioritised outcomes at the end of both surveys as well as other parameters such as feedback, initial condition and iteration effects. Discussion: This trial will provide evidence to inform decisions on the use of Multi-Round compared to Real-Time Delphi survey methods. Trial registration: NCT04471103. Registered on 14 July 2020.