Problem-based learning: measurable outcomes.

Problem-based learning (PBL) could potentially contribute to four key objectives in the education of doctors. (1) Motivating learning. Three studies show that students studying PBL problems choose fewer topics to study than those identified by the faculty, but one study of a critical care rotation showed that students were motivated to learn over a wider range of basic science topics than had been included in the basic science curriculum. (2) Developing clinical reasoning. One study compared methods of solving problems in PBL and conventional track curricula and suggested that PBL students work backwards from clinical information to theory, while conventional curriculum students tend to reason forward from theory. One study showed that computer searches provide knowledge for helping solve some PBL problems, and another study showed that specific knowledge in emergency medicine correlated with test scores. (3) Structuring knowledge in clinical contexts. A few studies show that PBL students perform less well on basic science examinations but better on clinical examinations. Educational outcomes, however, have been assessed quantitatively mainly by the U.S. National Boards of Medical Examiners Examinations or by clinical examinations with small samples. Only one study includes a power computation to assess type II error. There are no studies that examine how much variance occurs between PBL programmes in their curricular methods and outcomes. (4) Developing self learning skills. PBL students use a much wider range and number of resources than conventional track students. There is only one study comparing the knowledge of doctors trained by PBL and conventional curricula after the doctors have been in practice for a substantial number of years, and no studies of patient outcomes. Patient outcomes need to be assessed with randomized controlled trials, and sample sizes should be determined by power computations to avoid Type II error. Four possible methods of improving PBL would be to derive national and internationally accepted PBL curricula; to organize internationally accepted and psychometrically validated methods of evaluation; to develop attitudes among students and tutors to facilitate co-operative PBL teamwork; and to teach group process diagnostic skills.