Before embarking on any effort to improve decisionmaking, an agency must have an effective and practical deadly force policy; officers must understand the parameters of their authority. Since the 1985 U.S. Supreme Court decision in Tennessee v. Garner, most law enforcement agencies have adopted restrictive policies that rely on "defense of life" as the rationale for using deadly force; however, ambiguities often exist when officers attempt to apply policy in dynamic street situations. The deadly force triangle is a decision model designed to enhance an officer's ability to respond to a deadly force encounter while remaining within legal and policy parameters. The three sides of an equilateral triangle represent three factors: ability, opportunity, and jeopardy. All three factors must be present to justify deadly force. Further, trainers must understand survival physiology and survival stress management techniques to help officers improve their decisionmaking skills in deadly force situations. Practice through realistic simulation offers one of the best ways to prepare officers to handle deadly force decisions. This training strategy integrates classroom instruction on policies and decisionmaking models with open motor skill training to enable officers to apply their knowledge in dynamic, stressful situations that approximate real life. Participants' performances during dynamic training sessions should be evaluated and documented. 29 notes