In a multiple-reversal time-series design, additional plainclothes youth guidance officers were assigned to patrol and to issue juvenile warning citations in one of two target areas during school hours on weekdays. The presence and activity of these officers resulted in modest but consistent reductions in the number of criminal incidents reported in the target area. An untreated control area showed no consistent changes in the rates of criminal incidents. Issuance of juvenile citations appears to be a modestly effective crime control technology which may be implemented in a cost-efficient manner.

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.

Program evaluation can provide objective information relevant to decisions on program maintenance. A program to address problems in the preparation of criminal investigation reports in a metropolitan police department was evaluated. The program permanently altered environmental conditions under which reports were prepared to facilitate performance. Police officers, who had previously prepared reports without assistance, visited the Case Preparation Room to prepare reports with assistance from office personnel. Compared to reports prepared without assistance, reports prepared in the Case Preparation Room documented more case elements required by the state legal code for criminal prosecution, were completed in fewer days following arrests, and received higher ratings from Assistant District Attorneys. Operation of a permanent program available to approximately 945 officers proved a practical solution to improving the preparation of criminal investigation reports.