Identification and characterization of early and late prescribers in general practice.

National Health Service prescriptions written by general medical practitioners in one urban Area were analysed over a fifteen-month period to classify doctors into those who prescribed a named drug early or relatively later in its market life. A questionnaire, designed to answer a number of hypotheses intended to characterize these groups of practitioners, was mailed to the 100 doctors in each group. Statistical analysis of the results suggests that there are several identifiable characteristic differences between `early' and `late' prescribers. Early prescribers have larger list sizes than late prescribers and rely more on industrial sources for information about drugs.