Flanders 1985

Methods	Randomised controlled trial with four groups.
Participants	Country: USA. Setting: NA. Health problem: acne. Recruitment: other (screened as part of a larger study). Participants: college students (n=42).
Interventions	Contract features: Form: written; Parties: NA; Incentives: tokens; Co‐interventions: yes. Group 1: Non‐contingent contract (agreement to return self‐monitoring cards) with education and self monitoring medication card. Group 2: Contingent contract (agreement to return self‐monitoring cards with chance to win prizes for each returned) with education and self monitoring medication card. Group 3: Education and self‐monitoring card. Group 4: Waiting list.
Outcomes	Acne cream compliance rate and number of acne lesions.
Notes
Risk of bias
Item	Authors' judgement	Description
Allocation concealment?	Unclear	B ‐ Unclear