Information systems (IS) studies highlight that IS usage, a pre-requisite for IS diffusion, may be difficult to attain when usage is voluntary because users can resist using the system. User resistance may be overcome through the application of organizational controls. Control theory explains how users' actions and practices are shaped in line with organizational guidelines and procedures. This paper reports on a qualitative case study and shows how formal control mechanisms (behavior and outcome controls) can have a positive and conclusive impact on IS diffusion. The paper makes three contributions to knowledge. First, it proposes a model of IS diffusion, which explains how the application of outcome control mechanisms can lead to IS diffusion despite user resistance. Second, it suggests that IS diffusion paths are iterative, rather than smooth and linear. Finally, the paper demonstrates that despite a lack of reward expectancy, sanction expectancy can be effective during an IS diffusion process
