Instructional designs, embedding learning in meaningful contexts such as problem-based learning (PBL) are increasingly used for fostering expertise to prepare students for the demands of the future workplace. However, cognitive outcomes of these curricula in terms of expertise outcomes are not always conclusive. Based on the instructional implications resulted from research in the field of expertise development in general and in PBL curricula more specifically, we constructed and implemented a refined PBL design. With this redesign, we aimed for a more advanced level of (a) knowledge acquisition and use, (b) reasoning directionality, (c) diagnostic and problem solving accuracy. The aim of the present research was to compare the outcomes of a "traditional" and a "refined" PBL learning environment. For that purpose we measured the effects of the redesign on the students' expertise profile. An experiment was conducted in a second year course on International Marketing. In the study 75 students participated. Using a multidimensional coding scheme, constructed on the basis of results of expertise research, we analysed students' problem-solving performance. The results of this analysis indicate that the experimental students outperformed the control students in various aspects of expertise when analyzing the problem: The experimental group demonstrated a more extensive use of domain-specific concepts and inferences, more inductive reasoning, and both diagnoses and solutions of higher quality. (Contains 3 figures and 4 tables.)