Previous research has shown that, unlike novice physicians' performance, diagnostic quality of expert physicians improves when contextual information (the "Enabling Conditions") about a patient is available. The present study was designed to explore these findings further by systematically varying the typicality of enabling conditions and consequences (signs, symptoms, and complaints) of a case, and determining the effect of this manipulation on subjective disease probability estimations. Subjects were 25 sixth-year (resident) students and 30 experienced family physicians in the Netherlands. A significant interaction was found between expertise level and typicality of enabling conditions in cases with prototypical consequences, but not in cases with atypical consequences. The implications of these results are discussed in terms of the illness-script theory. Two figures and one table present study data. (Contains 20 references.) (Author/SLD)