Multi-Round Delphi method
The MRD survey comprised three rounds. Participants were asked to rate the outcomes on the same 9-point Likert scale as the RTD survey participants. The first round presented the same 87 outcomes to participants as those in the RTD. The five additional outcomes were added to round 2 of the survey based on stakeholder feedback. In round 1 of the Multi-Round survey, participants were asked to rate the outcomes and could suggest additional outcomes that were not already included in the Delphi survey.In round 2 of the survey, participants were shown the stakeholder group ratings for each outcome in bar chart format. As in Fig. Participants who fully completed round 1 were invited to complete round 2. Similarly, those that completed round 2 were invited to complete round 3. In rounds 2 and 3 of the Multi-Round survey, participants were shown how the stakeholder groups rated the outcomes in the previous round. The consensus criteria (Table At the end of both surveys (Multi-Round and RTD), outcomes meeting the consensus criteria ‘consensus in’ and ‘neither consensus in nor consensus out’ were carried forward to online consensus meetings for further discussion and voting with representative groups of stakeholders (parents/caregivers, healthcare providers and researchers/academics) to decide on the final COS [