Difficulties in a multipractice study.

A multipractice study with the aid of questionnaires concerning "The possible influence of patients' occupations on sterility" had to be given up, when three quarters of the general practitioners who originally enrolled failed to complete the investigation. To help other investigators involved in multipractice studies, an analysis was done of the causes of general practitioner drop out. This points to lack of motivation, a lack of knowledge of epidemiology, forgetfulness and too great a workload on the part of the general practitioner. In addition findings showed an over long period of study, a rather extensive and complicated questionnaire, the fact that sterility is a rare problem, and other more obscure circumstances.