How we developed this guidance

12 step process

1. The Delphi consisted of two expert panels: health and social care practitioners currently working in adolescent mental health, and adolescents and young people (aged x-y) with lived experience of mental health difficulties and related service use.
2. Panels were recruited by advertising on social media and third sector networks.
3. There were 21 practitioner participants and 22 young people participants.
4. Over a period of 5 months (Dec 2020 – April 2021), panel members completed 3 online questionnaires exploring the issues of importance identified in our qualitative interviews.
5. Participants were asked to rate their agreement on a 5-point Likert scale with a range of statements relating to our core domains of ‘who’, ‘when’, ‘how’, ‘what, and with what ‘outcome’.
6. They were also asked open-ended questions to obtain clarification and nuance, explore areas of contention and allow new ideas to be expressed. 
7. The study was carried out in 3 rounds, with analysis between each round.
8. The questionnaires for rounds 2 and 3 were then designed to build upon findings from the round before.
9. Open-ended responses were coded inductively and developed into further statements for rating.
10. Statements were considered to have reached consensus where 75% or more reported agreement. Statements not reaching consensus were re-examined.
11. Statements reaching consensus amongst both young people and practitioners progressed for possible inclusion within a set of ‘good practice indicators’.
12. Where statements were agreed early in the Delphi and then superseded by more precise follow-on statements, only the latter were retained.