In 2013, the president of Rwanda asked us for evaluation results from across the continent that could provide lessons for his country’s policy decisions. One program tested in Kenya jumped out, and the Rwandan government wanted to know whether it would likely work in Rwanda as well. “Sugar Daddies Risk Awareness,” an HIV-prevention program, was remarkably effective in reducing a key means of HIV transmission: sexual relationships between teenage girls and older men. A randomized controlled trial (RCT) found that showing eighth-grade girls and boys a 10-minute video and statistics on the higher rates of HIV among older men dramatically changed behavior: The number of teen girls who became pregnant with an older man within the following 12 months fell by more than 60 percent.