This study compared the diagnostic performance of 612 second-, third-, fourth-, fifth-, and sixth-year students from three Dutch medical schools who were educated in either a problem-based, an integrative, or a conventional curriculum. The students were presented with 30 carefully selected clinical cases to diagnose. The study found that, overall, the students trained within the problem-based and integrated frameworks displayed better diagnostic performance than students trained within a conventional curriculum. No overall differences were found between the problem-based and the integrated curriculum, although second- and third-year students from the latter excelled the comparable year groups in the other curricula formats. The study concludes that integration between basic and clinical sciences and an emphasis on patient problems may be the critical factors determining superior diagnostic performance rather than whether a curriculum is self- or teacher-directed. (Contains 16 references.) (MDM)