User involvement has long been considered a critical component of effective system implementation. However, the perspective has suffered from mixed results of empirical tests and the lack of a theoretical explanation for the relationship (Ives and Olson, 1984; Baroudi, et al., 1986). Our purpose is to present a theoretically-grounded perspective to account for effects of involving users during implementation, and to provide an initial test of this perspective. We propose that: (1) system implementation represents a threat to users' perceptions of control over their work and a period of transition during which users must cope with differences between old and new work systems; (2) user involvement is effective because it restores or enhances perceived control. Results of a field experiment designed as a preliminary test of this perspective are discussed.