The medical student working singly or in small groups will, with Preventive Medicine faculty assist- ance, identify a question in the broadest sense in medicine which can best be answered by a population- based study. This could include comparison of therapeutic techniques, status of knowledge by health provider or consumer about certain conditions or costs of care, problems of organizing health services, ethical problems, or any other population-based question amenable to study. Building on the second year experience, the project will involve identifica- tion of a question, design and conduct of the study, appropriate analysis of data and a written and oral presentation.