Abstract
Background: Interest runs high these days in developing "evidence-based" reviews to provide guidelines for instructional practice. However, we lack careful documentation of the ways in which the practices of problem-based learning (PBL) vary across groups and across implementations. A necessary starting point for developing any sweeping conclusions about the efficacy of PBL as an instructional innovation, therefore, is that we begin to become more articulate about what it is that people do when they say they are doing PBL. Summary: A proposal is offered for a new initiative in medical education research, one focused on documenting the range of practices employed in different implementations of PBL. A vital facet of this initiative would be the development of a shared corpus of video recordings referred to here as the "PBL TalkBank database." Conclusions: We propose that medical educators adopt the tradition employed in linguistics and communication studies of creating shared data corpora. The corpus in this case would consist of recordings, transcripts, and research notes documenting PBL practices in different PBL curricula. Preliminary work has been undertaken to develop such a database, and we invite the participation of other researchers.