But, she added, “It’s possible that potential perpetrators could encounter individuals who have received training and just move on to more vulnerable individuals.”

To address sexual assault comprehensively, she and other experts said, colleges as well as high schools and middle schools should take multifaceted approaches that considered root causes of violence against women and men, compelled bystanders to intervene and gave guidance on healthy relationships.

Charlene Y. Senn, the lead author of the Canadian study and a social psychologist at the University of Windsor, did not disagree. “It gives women the knowledge and skills they need right now, but the long-term solution is to reduce their need to defend themselves,” said Dr. Senn, who also supervises a campus bystander program.

The two-year trial at universities in Calgary, Alberta, and Windsor and Guelph in Ontario, expanded on components of other resistance programs and added a training session on sexuality and relationships.

Students, largely recruited in psychology classes, could take all four three-hour sessions over a weekend or in weekly classes. The structure was purposely dynamic, and included role-playing, discussion and problem-solving.

One major hurdle, Dr. Senn said, was that the young women had been taught just to be on guard against the stranger rapist — to fear the shadowy campus at night, the deserted parking lots. Rape by an acquaintance or a romantic partner, far more common, is not a concept they had considered, she said.

At a session Lindsey Boyes attended at the University of Calgary, she said she was startled to learn that if someone had sex with a person who was intoxicated, the act could be defined as sexual assault: A person who is mentally incapacitated because of alcohol or drugs cannot legally give consent.