Publisher Summary This chapter delineates the role of measuring performance in comparison to established standards, in incident prevention process. Measurement, together with feedback of results to individuals and teams responsible for performance, provides the foundation for an effective accountability system. Measurement and feedback also facilitate the growth of employee pride, enthusiasm, and job satisfaction. An effective measurement and feedback system allows managers and others accountable for performance to stay up-to-date on implementation efforts. Progress beyond the "Plan" step is dependent upon a system for measuring results and providing timely feedback to individuals and teams accountable for performance. The chapter then gives a detailed example of working of a warehouse, to emphasize the role of performance measurements in critical work. The critical work to sustain incident-flee operations tends to be low visibility, with neither the actual performance of the work nor the status of the work typically visible to management. The chapter ends with a detailed description of characteristics of effective measurement and feedback systems.