The use of the 'blind' problem in teaching epidemiology

In the use of the case-study or problem-solving method of teaching epidemiology, the technique of the 'blind' problem, namely the withholding of the diagnosis of the disease until the end, presents many advantages. The student is forced to confront the purely epidemiological data without being prejudiced by his preconceived notions about the disease in question. In the study of an individual clinical case the objective is to make a diagnosis so that an accurate prognosis and specific treatment may be determined. So, in the study of an epidemic or outbreak (an epidemiological case) the objective is to establish a source of infection, a mode of spread or an aetiological factor, in order to predict a future trend and institute specific control measures. The 'blind' problem creates suspense, enhances the intellectual challenge, and permits the student and discussion leader to test a variety of hypotheses purely on the basis of the epidemiological evidence presented. An example of a localized epidemic is presented to illustrate these points.