The Diffusion of an Innovation among Physicians

problem is reported in this paper. The population is physicians in four cities; the item whose use was spreading was a new drug; and the study focused on the ongoing social processes which finally led to widespread adoption of the drug by these physicians. Data were collected 15 months after a new drug with wide potential use, here called gammanym, had been placed on the market. By this time almost all the doctors in relevant specialties in the four cities studied had used the drug, some almost immediately, others only after a considerable interval of time. The research problem, stated most concretely, is this: What were the social processes which intervened between the initial trials of the drug by a few local innovators and its final use by virtually the whole medical community? The results reported below concern the effectiveness of networks of interpersonal relations at each stage of the diffusion process. The study is to be reported in full elsewhere (2); a pilot study has already been reported upon (9). A separate article by one of us describes the cumulative research experiences which led to the decision