Behavioral information acquisition strategies in a diagnosis problem are formulated and examined and the effects on these strategies of both information presentation and user training are tested. Twenty-five subjects participated in an experiment in which the decision maker was required to solve a set of medical diagnosis problems. A matrix of 7 illnesses and 11 possible tests was presented on a micro-computer; the task was to diagnose the correct illness with the minimum number of tests. The results were analyzed using verbal protocols and a computerized record of the user's responses. The results confirm the use of certain behavioral strategies, in particular concentration on a small subset of classes in a regular pattern, and a positional effect on the choice of tests was also detected. The implications of these results on the design of management information systems are discussed.