The Fourth R — Teacher-Delivered Healthy-Relationships Curriculum, Ontario (Contested Evidence)

The Fourth R, developed by David Wolfe and colleagues and now run by the Centre for School Mental Health at Western University in London, Ontario, treats relationships as a 'fourth R' alongside reading, writing and arithmetic. It is a 21-lesson curriculum taught within existing health and physical education classes by teachers who receive about six hours of training. Developers cite a cost of roughly $16 per student.
The 2009 cluster-randomised trial (Wolfe et al., Archives of Pediatrics & Adolescent Medicine) covered 30 schools and 1,722 ninth-graders followed for 2.5 years. The centre's summary reports physical dating violence about 2.5 times greater among control students than intervention students. A 2011 follow-up (Crooks et al.) found a buffering effect on violent delinquency for maltreated youth.
The independent rating is less favourable. CrimeSolutions reviewed three randomised trials, including a Bronx middle-school trial, and rates the programme Ineffective: it reports only small significant decreases in dating violence (7.4% versus 9.8%) and sexual-harassment victimisation, and no significant effects on perpetration, peer violence, substance use or sexual activity.
The practice is included as a cautionary case: a widely adopted, low-cost, teacher-delivered model whose effects are modest and differ by outcome, sample and rater.

Read the full analysis: https://www.csmh.uwo.ca/publications/fourth-r-research.html