We propose a model to study expectation confirmation in information systems. The proposed model is based on the assimilation-contrast model and prospect theory, and suggests that both are needed to account for the magnitude and direction of the deviations between experiences and expectations. Using the technology acceptance model’s (TAM) primary construct, namely perceived usefulness, expectations and experiences were conceptualized and operationalized to test our model. Data were collected in a field study from 1,113 participants at two points in time. Using polynomial modeling and response surface analysis, we demonstrated that our model offers a good explanation of the relationship among information systems expectations, experiences, and use. We discuss theoretical and practical implications.