Systematic reviews – “A systematic review summarises the results of available carefully designed healthcare studies (controlled trials) and provides a high level of evidence on the effectiveness of healthcare interventions. Judgments may be made about the evidence and inform recommendations for healthcare” .
Qualitative studies – “Qualitative research is used to explore and understand people’s beliefs, experiences or behaviours. It asks questions about how and why. Researchers use methods like focus groups and interviews” .
Consensus processes – Consensus processes are surveys, meetings and discussions where the opinions of relevant experts are drawn together to try to reach agreement, or “consensus” about a particular topic. Experts can include patients and carers with experience of a condition. The process of reaching consensus can involve methods like surveys and consensus meetings.
Delphi surveys – A method to gather the opinions of a group of experts on a subject and try to reach agreement, or “consensus” amongst this group about a particular topic. Experts can include patients or carers with experience of a condition. Delphi surveys are usually questionnaires and can involve the experts voting to rate their opinion on a topic in two or more rounds of the survey. Plain language summaries about Delphis  and core outcome set studies  are available from the COMET website.
PoPPIE Working Group – PoPPIE stands for People and Public Participation, Involvement and Engagement. PoPPIE’s international membership will be leading COMET’s public participation, involvement and engagement activities.
The COMET Initiative – COMET stands for the ‘Core Outcome Measures in Effectiveness Trials’ Initiative. It involves people from around the world and in many different areas of health and social care and was set up to help in two main ways:
• to provide the COMET database as a central point where researchers, clinicians and patients can find core outcome sets that have already been developed or are still under development.
• Provide materials to support the teams who are working on core outcome sets