This chapter reviews the main lesson learned to date about the diffusion of preventive innovations. It discusses the application of these lessons to such issues as preventive health behavior (especially heart disease prevention), family planning, and energy conservation. I shall argue here that preventive behaviors are particularly difficult to bring about, whether they entail going on a low-salt diet, installing a burglar alarm system in one's home, or purchasing flood insurance. Prevention campaigns that have adopted strategies drawn from diffusion theory have tended to be more effective than other preventive efforts.

Preventive innovations

Diffusion is the process by which an innovation is communicated through certain channels over a period of time among the members of a social system (Rogers, 1983: 5). Thus, diffusion is a type of communication – the communication of messages about new ideas. Communication is a process in which participants create and share information with one another in order to reach a mutual understanding (Rogers & Kinkaid, 1981). Although early definitions of communication implied a one-way process, we now think of communication as a two-way process of convergence. Such convergence (or divergence) occurs as two or more individuals move toward one another (or farther apart) in the meanings they ascribe to events.

One important type of message deals with innovations. An innovation is an idea, practice, or object that is perceived to be new by an individual or other unit of adoption (Rogers, 1983: 35). Many innovations offer an immediate increase in some desired quantity.