The Kansas City preventive patrol experiment was the first major study using an experimental design in law enforcement and is now considered a seminal policing study. It sought to test the effectiveness of routine preventive patrol, and the results showed that this form of patrolling, then considered a fundamental policing activity, was ineffective at achieving the desired effects, preventing crime. This conclusion and the subsequent debate ultimately resulted in police departments searching for other strategies to combat crime. Major strides were made in research and policy as a direct result of the study.

Prior to the study, patrol was seen as the most effective police tactic to prevent crime. Patrol, it was thought, prevented crime through omnipresence and apprehension. Omnipresence was achieved though random patrol where ...