The medical education community is reflecting increasingly on the role and nature of research in the field. Useful sources of data to include in these reflections are a description of the topics in which we are investing our energies, an analysis of the extent to which there is a sense of progress on these topics, and an examination of the mechanisms by which any progress has been achieved. This article presents the results of a thematic review of the medical education research literature in four key journals since the turn of the 21st century. It describes four examples of areas in which the community appears to be investing its energies: curriculum and teaching issues, skills and attitudes relevant to the structure of the profession, individual characteristics of medical students, and the evaluation of students and residents. A discussion of the recent publications in these domains highlights a distinction between thematic categories of research, in which many members of the community are working on the same topic, and programmatic lines of research, in which members of the community are working together toward the shared goal of consensual understanding. The author suggests that community-level, programmatic lines of research are necessary to build knowledge and understanding of a domain and that, in the absence of such communal effort, the value of research is limited to the uncoordinated accrual of information.