On August 30, 2017 from 2:00-3:30 p.m. Eastern, the Bureau of Justice Assistance (BJA) Smart Policing Initiative (SPI) presented a webinar on “Reducing Crime and Improving Public Trust through Collective Efficacy: Evidence from Miami and Brooklyn Park”. This webinar translated collective efficacy theory into practice. It provided definitions of collective efficacy and informal social control and how they relate to crime reduction. It demonstrated the importance of community building and described how the police not only engage the community, but build relationships in high crime neighborhoods. Ms. Shellie Solomon and Dr. Craig Uchida of Justice & Security Strategies, Inc. and Inspector Bill Barritt of the Brooklyn Park Police Department guided us through the intricacies of collective efficacy. They provided concrete and useful examples from the field – Miami-Dade County and Brooklyn Park, MN – and demonstrated how to implement collective efficacy within police agencies and in neighborhoods.