Literature about data-use has tended to overstate the importance of data-providers (ie, of researchers), and to understate the importance of data-users (ie, of managers). Because data-use is just as much under the influence of the user as of the provider, the disparity in importance given to researchers and managers is improper. A model of data-use is developed here from the point of view of the data-user, based on an analogy between rational decision-making and Bayesian analysis. The model then empirically illustrates how different decision-makers use identical data in different ways. Specifically, the model shows how decision-maker predispositions shift the balance between the two fundamental decisions in data-use: deciding to act or deciding to gather more data.