Wolfe 2009.

Methods	Cluster‐RCT. Schools stratified by size (≥ 500 vs. < 500) and location (urban vs. rural) and randomly assigned to intervention or control
Participants	1722 9th grade students (aged 14‐15 years; 52.8% girls, 47.2% boys) from 20 public schools, Canada
Interventions	Intervention: "Fourth R: Skills for Youth Relationships", incorporating personal safety and injury prevention, healthy growth and sexuality, and substance use and abuse. Sessions were integrated with core health lessons. A total of 21 75‐minute lessons were delivered by normal health teachers who had received 6 hours of additional training. 968 students Control: taught on the same topics but without the teachers having received any training or programme materials. 754 students
Outcomes	Self reported physical dating violence, attitudes towards dating violence and negotiation skills, as measured by the Conflict in Adolescent Dating Relationships Inventory
Follow‐up	2.5 years post‐intervention
Notes	‐
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Random sequence generated by tossing a coin
Allocation concealment (selection bias)	High risk	Coin toss allows investigators and participants to see their allocation
Incomplete outcome data (attrition bias) All outcomes	Low risk	No loss to follow‐up (all 1722 students assigned to groups were included in analysis)
Selective reporting (reporting bias)	Low risk	All outcomes reported fully (n and %)
Blinding of participants and personnel (performance bias) All outcomes	High risk	Blinding not possible. Teachers delivering intervention received some additional training. No mention of monitoring to assess adherence to protocol
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not stated