Chart detailing policing models from 1975 to 2010. The text reads: An effective public order policing model has several components. The foundation begins with scientific theory and evidence based on research and tested techniques. Effective contemporary crowd control methods used by American, Canadian, and British agencies support these techniques. Police procedures strongly influence law enforcement training, thus, affecting officers’ responses. The text on the pyramid reads: Science-Based, Event-Tested Theoretical Understanding of Crowds; Police Policy, Knowledge, and Philosophy; Police Training; and Police Response.