This is the report of a think tank series of webinars organized by the Global HIV Prevention Coalition Secretariat in response to demands from partners for a new and more effective way of measuring combination HIV prevention. Held in May and June 2022, the series consisted of five sessions that examined defining risk, measuring the coverage, outcomes and impact of prevention programmes, outcomes and impact, and innovative measurement approaches. The series results are supposed to inform Global AIDS Monitoring guidance, measurement frameworks of the Global Fund, and potentially other surveys such as Demographic and Health Surveys, Population-based HIV Impact Assessments and Integrated HIV Bio-behavioural Surveillance.