Table 4 Inclusion and exclusion criteria

Inclusion criteria

 Study population included children and young people between the age range of 0–< 24 years

 PPI activities occurred with children and young people aged 0–< 24 years

 Reports published in 2018 up to 28th February 2022

 Any interventional or observational study

Exclusion criteria

 Not relevant (study population didn’t include 0–< 24 years)

 Reports waiting to be published

 Reports that do not mention PPI

 Reports that do not include children and young people in PPI activities

 Unable to separate CYP population (as PPI advisors) from other populations (for example, parents or carers)

 Insufficient information on PPI

 Describes ‘engagement’ not involvement

 Hard to distinguish between the actual research methods and PPI