THE DESIGN OF THE EXPERIMENT IS EXAMINED TO SEE WHETHER THE CONDITIONS EXPECTED WERE ACTUALLY BROUGHT ABOUT THE CONDUCT OF THE EXPERIMENT ITSELF IS EXAMINED TO DETERMINE IF EXPERIMENTAL CONDITIONS WERE MAINTAINED. THE TYPES OF DATA USED IN EVALUATING THE FINAL OUTCOMES OF THE EXPERIMENT ARE REVIEWED. 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 EQUALING 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. IN OTHER WORDS, THE OPERATIONAL CONSEQUENCES OF THE EXPERIMENTAL DESIGN WERE NOT ADEQUATELY CONSIDERED BY THE ORIGINAL RESEARCHERS AND WERE SO DIFFERENT FROM THOSE EXPECTED THAT THE VALIDITY OF THE DESIGN AS A MEANS FOR GREATLY REDUCING PATROL LEVELS IN A SUBREGION MUST BE QUESTIONED. 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 CRIMEDIRECTED PATROL EFFORTS. THE APPENDIX CONTAINS A SUMMARY OF DEFINITIONS OF TECHNICAL TERMS USED IN THE PROBABILITY EQUATIONS AND A SUMMARY OF THE KEY IDEA OF EACH EQUATION. FOR A RESPONSE TO THIS ANALYSIS, SEE NCJ-34037. (AUTHOR ABSTRACT MODIFIED)