Physician and epidemiologist Gary Slutkin has worked in more than 20 countries, fighting infectious diseases like cholera, HIV/AIDS and tuberculosis. After a decade abroad, he returned to the United States in 1994 and found an acute problem here: gun violence. He began to study the issue and saw familiar patterns: "I just said, 'This is behaving exactly like an infectious disease.' This is the same kind of map, same kind of clustering. Someone has picked this up from someone else, and they pass it on to someone else, and pass it on to someone else."

Slutkin decided to approach gun violence the same way he curbed cholera and AIDS — by convincing people to change their behaviors. And that doesn't happen by threatening to punish them: "You're not going to punish people out of AIDS." Rather, he found that training community members to spread the message about safe behavior could get people to rethink risky behaviors.

He decided to try the same approach to curb violence in the U.S. In 2000, he started CeaseFire (later renamed Cure Violence), which trains and deploys outreach workers, or "violence interrupters," in high-risk communities. The program has also been used in Honduras, Iraq, Mexico and other countries and profiled in the acclaimed 2011 documentary, The Interrupters.