Before Rodrigo Guerrero became Mayor of Cali, Colombia in 1992, no one had ever really thought of urban violence as a public health issue. 

But Guerrero is a Harvard trained epidemiologist, so as Mayor, he decided to analyse the data on murders in the city and use it to identify the biggest risk factors for violence. He then applied that data to his policies. 

One example: a firearms ban that made it illegal to carry a firearm outside the home on weekends.

Guerrero joins us to talk about the policies they’ve implemented in Colombia and the lessons learned that he hopes to apply in other cities around the world. He’s is in Chicago as part of the Urban Youth Violence in the Americas Action Tour, which takes place here this week.