Table 2.

Characteristics of case study trials

Setting (population)	Design	Intervention	Summary of PPI	Stages of trial involving PPI
Community health (adults)	Individually randomised, two-arm pilot RCT	Counselling and psychotherapy	Primary role of PPI was to ensure study met the needs of target population. x2 PPI members contributed a few times during set up. x1 PPI member on TSC	Grant application Planning Ongoing oversight (TSC)
Primary care (adults)	Cluster-randomised two-arm RCT	Organisational, behavioural	Role of PPI to put pressure on the trial team, emphasising participants’ contribution/involvement and ensuring patient-centredness. (PPI perspective) Role of PPI to ensure research will benefit patients and that what we are doing in trial meets their needs/is important to them. (TM perspective) No PPI members on TMG. x2 PPI members in TSC and large PPI group of 10 members who meet every 3–4 months (including those on TSC). 2 additional members dropped out during the trial.	Planning Ongoing oversight (TSC) Implementation
Educational setting (adolescents)	Two-arm cluster RCT (feasibility and definitive)	Public health, behavioural	Same PPI group used throughout. x5 PPI members met once a year	Planning Implementation
Primary care (children)	Individually randomised, three-arm RCT	Pharmacological	Purpose of PPI is to ensure trial processes are acceptable to target patient group. x10 PPI members, ad hoc meetings every 2–4 months (same members throughout) x1 PPI member of TSC	Development/planning phase Ongoing trial oversight
Secondary care (adults)	Two-arm RCT	Surgical	Surgeons recruited PPI members (small number). 2–4 patients were asked their views during application stage. Different PPI people then became members of the TSC. But also looked at trial documentation outside of the TSC. x2 PPI members met every 5–7 months. 1x PPI member of TSC.	Planning/grant application Ongoing oversight
Community health (adults)	Two-arm RCT	Behavioural	Purpose of PPI to ensure taking account of the patient voice. x20 PPI members. Met every 5–7 months. PPI members included in TMG and TSC	Planning Ongoing oversight
Secondary care (adults)	Two-arm multi-centre RCT	Surgical	Consulted larger ‘general’ patient group on study design during application stage. Then a PPI group which more relevant condition experience was established specifically for study. The same group continued to support the study throughout its duration.	Planning/grant application Planned to use for dissemination once at that stage.
Primary care (adults)	Pilot Two-arm RCT	Behavioural	Met with different patient groups and forum to inform grant application, study approach and documentation. Specific numbers not indicated, however one group x 10 people.	Planning/grant application