The effects of a carefully monitored and increased police patrol on the report of crime were examined in four patrol zones. Overall patrol movement was increased to four times normal levels and slow patrol movement (under 20 mph) to around 30 times normal levels for 10 days. The patrol was active in two zones between 9:00 a.m. and 5:00 p.m. and in the other two zones between 7:00 p.m. and 3:00 a.m. A multiple‐baseline design and time‐series statistical analyses showed statistically reliable changes in reported levels of Part I crime (such as robbery, burglary, and aggravated assault) during both night patrols, but not in the day patrols. In both night‐patrol zones, there were also reliable increases from saturation patrol to postsaturation patrol in report of Part I crime after the night patrol was terminated. Neither of the day patrols showed significant crime report changes on termination. Despite statistically reliable decreases in report of crime during nighttime hours, the value of saturation patrolling as a crime‐prevention technique was questioned on cost/benefit grounds.

The significance of a helicopter patrol procedure directed toward prevention of home burglaries was evaluated from experimental and cost-benefit perspectives. The helicopter patrolled one city zone from 9 a.m. to 5 p.m. for two 12-day periods. Each 12-day period was separated by a baseline period in which only normal patrol-car levels were maintained. Significantly reduced burglary levels during the intervention periods, compared to baseline periods, documented the experimental significance of the helicopter procedure. The cash costs of implementing the patrol procedure were compared to two estimates of the resulting cash benefits. This latter cost-benefit analysis was supplemented by a discussion of the intangible costs and benefits of the helicopter procedure. Taken together, these analyses documented that the marginal costs of the helicopter intervention were exceeded by all estimates of benefits.

In most social evaluation research it is difficult to achieve the degree of experimental rigor possible in an applied behavioral study. This study illustrates how the evaluation researcher can increase experimental rigor in the analysis of social interventions. In the first evaluation, a variation of the time‐series design that offered maximum experimental control given the limitations of the situation, was employed to evaluate the effects of a specialized home‐burglary police patrol. This design revealed that no effects could be attributed to the patrol. In the second evaluation, a multiple baseline‐like design was possible in determining the effects of a police walking patrol. This design revealed that the patrol produced an increase in crime reporting but not in arrests. Social interventions often occur in a manner that allows varying degrees of experimental analysis. The evaluation researcher must attain optimal experimental analysis given the limitations of each social intervention.

Tachograph recorders were installed in 224 vehicles of a metropolitan police department to monitor vehicle operation in an attempt to reduce the rate of accidents. Police sergeants reviewed each tachograph chart and provided feedback to officers regarding their driving performance. Reliability checks and additional feedback procedures were implemented so that upper level supervisors monitored and controlled the performance of field sergeants. The tachograph intervention and components of the feedback system nearly eliminated personal injury accidents and sharply reduced accidents caused by officer negligence. A cost-benefit analysis revealed that the savings in vehicle repair and injury claims outweighed the equipment and operating costs.