“Efficiency” means getting a task done with a minimum expenditure of time and effort; “effectiveness” means doing a better job to produce an intended or expected result; and “enabling” means having the ability to do something one could not do previously. This guide provides measures of efficiency, effectiveness, and enabling for various information technologies. Each chapter focuses on a specific police technology. The format for each chapter is the same. It first describes the technology, followed by a discussion of the resulting benefits, a summary of responses about the system, and outcome measures. The technologies addressed are automated field reporting systems, computer aided dispatch systems, records management systems, arrest and booking systems, automated fingerprint identification systems, and crime analysis and mapping systems. One appendix provides an overview of information technology in policing. Topics discussed are police communications centers, patrol operations, crime and intelligence analysis, problem solving, investigations, and arrest and booking. A second appendix provides supplementary information on the assessment of information technologies, including relationships among the three “E’s” and outcome measures for capturing the three “E’s.”