Research Article Epidemiology for the uninitiated. What is a case? Dichotomy or continuum? Br Med J 1978; 2 doi: https://doi.org/10.1136/bmj.2.6141.873 (Published 23 September 1978) Cite this as: Br Med J 1978;2:873 Article Related content Metrics Responses Peer review This is a PDF-only article. The first page of the PDF of this article appears below.