Foubert 1997.

Methods	Cluster‐RCT. The methods state that fraternity classes were "assigned" to experimental or control conditions but does not state whether this assignment was random. However, 2 subsequent studies carried out by the same author testing the same intervention in different settings (Foubert 1998 and Foubert 2000) use random allocation, we have presumed this study to be a cluster‐RCT
Participants	114 fraternity members (male only; mean age 18.8 years (intervention group), 18.7 years (control group) at a university, USA
Interventions	Intervention: rape prevention peer education programme including lecture and video. Delivered by 4 male peer educators who followed a prepared script. The intervention was delivered as a single 1‐hour session. 76 students Control: no intervention. 38 students
Outcomes	Belief in rape myths as measured by the Rape Myth Acceptance Scale
Follow‐up	2 months post‐test
Notes	‐
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not stated
Allocation concealment (selection bias)	Unclear risk	Not stated
Incomplete outcome data (attrition bias) All outcomes	High risk	Attrition: intervention group 41% (31/76); control group 16% (6/38). Much higher rate of attrition in intervention arm than in control arm. Reasons for attrition not provided. High risk of attrition bias
Selective reporting (reporting bias)	Low risk	All outcomes reported fully (number of participants, means and SDs provided)
Blinding of participants and personnel (performance bias) All outcomes	High risk	Blinding not possible. Personnel delivering the intervention were trained and asked to follow script but no mention of objective ascertainment of adherence to study protocol, creating high risk of performance bias
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not stated