Towards a program of focused and applied curriculum research.

Though hundreds of journal pages have been packed with studies describing, analyzing, and synthesizing the benefits of Problem-based Learning (PBL) over conventional curricula, we still don't really know why. Currently it is impossible to say which of the various elements contributes to any incremental student learning. We need to apply the scientific method to studies of curriculum delivery. Accumulating evidence from strong studies in messy real-world situations will eventually yield important insights and instrumental truths for real medical schools that teachers and administrators can then implement. Examples of feasible experimental designs might include a factorial study. More effective curriculum development is possible only through a renewed applied research agenda that is both focused and grounded in the real world.