This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book deals with problems in performance measurement. The measurement of individual performance allows for rational administrative decisions at the individual employee level. It provides the raw data for the evaluation of the effectiveness of such personnel-system components and processes as recruiting policies, training programs, selection rules, promotional strategies, and reward allocations. It also provides the foundation for behaviorally based employee counseling. In this counseling setting, performance information provides the vehicle for increasing satisfaction, commitment, and motivation of the individual. Performance measurement allows the organization to tell employees something about their rates of growth, their competencies, and their potentials. The measurement of performance has occupied the attention of applied psychologists for several decades. The graphic rating scale was introduced in 1920 as an attempt to capture something of the more "impressionistic" characteristics of energy expenditure and its effectiveness.