The concept and measurement of information systems (IS) effectiveness is discussed and results of a field study are presented. The literature on organizational effectiveness suggests that defining and measuring IS effectiveness via user perceptions is both appropriate and practical. A popular construct, user information satisfaction (UIS), is examined and several instruments purporting to measure UIS are discussed. The theoretical bases for a number of studies of IS using this measure are reviewed and it is concluded that theories and models from the behavioral sciences offer a sound basis for understanding and measuring IS effectiveness. A particular model of IS behaviors grounded in well-known behavioral theories is offered. The results of an industry survey of 848 IS professionals and user-managers in eight firms are presented and shown to lend support to the model. Deficiencies in the UIS construct arc highlighted and an alternative definition of IS effectiveness is proposed and motivated.