What's So Good About Problem-Based Learning?

In a systematically designed and controlled experiment conducted in a naturalistic in-structional setting, we examined adult students' learning of two concepts. Two intact classes taught by the same instructor were assigned to one of two conditions. In one class, in-struction was problem based for one concept. For a second concept, lecture/discussion was the exclusive method. In the other class, matching of concept and method (problem based or lecture/discussion) was reversed. Two forms of assessment of learning occurred six and 12 weeks following instruction. At the initial assessment, the lecture/discussion group showed superior learning for one concept and the groups performed equivalently for the other concept. At the later assessment, however, the two groups showed equivalent ability to access each of the concepts, but each group showed superior explanation of the concept for which they had experienced problem-based learning. Results support the hypothesis of integration of new information with existing knowledge structures activated by the problem-based experience as the mechanism by which problem-based learning produces its benefits.