This chapter outlines an information-processing model of clinical decision-making which is described as a function of the task, the decision maker, and the context. Attributes of the task, the decision maker, and the decision environment are highly interrelated and often interdependent. They directly affect the use of clinical evidence. We argue that information processing is modified significantly by the decision-making context and decision task characteristics. Knowledge of clinical decision-making is therefore becoming increasingly important when designing an intervention that will produce sustained behavioural change. An exploration of the context and information seeking aspects of prescribing is emerging as a first step towards building the concept of task-specific decision support design.