Kansas City Preventive Patrol Experiment

Dan Keller

Police patrol strategies have traditionally been based on two widely accepted hypotheses. First – that visible police presence prevents crime by deterring potential offenders. Second – that the public’s fear of crime is diminished by such police presence.

The Kansas City, Missouri Police Department developed the Kansas City Preventive Patrol Experiment designed to measure the impact that routine police patrol had on the incidences of crime and the public’s fear of crime. The Experiment was conducted from October 1, 1972, through September 30, 1973, and evaluated by the National Policing Institute.

Three controlled levels of routine preventive patrol were used in the experimental areas.

(1) One area, termed “reactive” received no preventive patrol. Officers entered the area only in response to citizen’s calls for assistance. This, in effect, substantially reduced police visibility in the area.

(2) In the second area, called “proactive”, police visibility was increased two to three times its usual level.

(3) In the third area, termed “control”, the normal level of patrol was maintained.

The experiment was designed to answer the following questions:

(1) Would citizens notice changes in the level of police patrol?

(2) Would different levels of visible police patrol affect reported crime?

(3) Would citizen’s fear of crime and attendant behavior change as a result of differing patrol levels?

(4) Would citizen’s degree of satisfaction with police change?

Analysis of the data gathered revealed that the three areas experienced no significant difference in the level of crime, citizens’ attitudes towards police services, citizens’ fear of crime, police response time, or citizens’ satisfaction with police response time.

The following findings were discovered as a result of the Experiment.

Citizens did not notice the difference when the frequency of patrols was changed.
Increasing or decreasing the level of patrol had no significant effect on residential and commercial burglaries, auto thefts, robberies or vandalism crimes.
The rate of which crimes were reported did not differ significantly across the experimental beats.
Citizen reported fear of crime was not affected by different levels of patrol.
Citizen satisfaction with police did not vary.

In summary - there is little evidence to suggest that increased police patrol deters crime.

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