What happened to patrol operations in Kansas city? A review of the Kansas city preventive patrol experiment

This paper reviews important aspects of the design, execution, and evaluation of the Kansas City Preventive Patrol Experiment. The focus is on the operational behavior of the patrol force during the experiment and not on before-and-after crime statistics. Where appropriate, simple probabilistic models are employed to estimate frequencies of preventive patrols and response times in each of the experimental areas. These models, together with experimental data, demonstrate that (1) typical patrol intensities in Kansas City are not large enough to encompass the range of patrol intensities experienced in other cities, and (2) patrol visibility in the depleted areas (the reactive beats) due to responding calls for service is relatively quite large, perhaps even equalling the pre-experimental levels during high workload periods. Such models also demonstrate that travel distances into the reactive beats should not be markedly increased, as the researchers had expected.Based on models and experimental data, the analysis indicates that the particular experimental design used in Kansas City resulted in a significant continued patrol presence in the depleted areas, with little increase in travel times in those areas. This suggests two policy conclusions: (1) great caution should be used in attempting to induce the general value of a visible patrol presence from the results of the Kansas City Preventive Patrol Experiment; (2) patrol administrators in other cities could, on a day-by-day basis if need be, remove conventional patrol coverage from certain beats and markedly increase manning in others nearby without incurring significant degradations in service (either actual or perceived) in the depleted areas. This second possibility facilitates the implementation of crime-directed patrol efforts.