At its core, Diffusion of Innovation is a book about social change, given Rogers' definition of social change being a sequential process of invention and diffusion. "Diffusion is the process by which an innovation is communicated through certain channels over time among the members of a social system" (Rogers, 2003, p. 11). Rogers scientifically studies innovation in terms of innovation-development and innovation-decision.
Innovation-development is the process by which an innovation begins with a perceived need. The solution to the need is then researched, developed, and commercialized. Once in product form, the innovation diffuses and is adopted, with the final stage of the process being the consequences of adoption or rejection of a particular innovation. Rogers is careful to note that not all innovations follow the sequence exactly nor necessarily complete all the steps in the process. Nevertheless, diffusion research studies over time generally acknowledge innovation-development in these terms.
Beyond the development of an innovation lies the sociology of who adopts the innovation and possible explanations for their choice. The innovation-decision is defined as the process in which an individual moves from knowledge of an innovation, being persuaded in favor of accepting or rejecting the innovation, the adoption decision, implementing that decision and finally coming to a resolute stance on whether or not the adoption decision was correct and thereby enduring. Perhaps Rogers is most recognized for his conceptual device categorizing adopters on the basis of their innovativeness. Rogers measures innovativeness along a normal frequency distribution and divides adopters into five categories: innovators, early adopters, early majority, late majority, and laggards. After a thorough review of diffusion research, Rogers is able to make generalizations throughout his book concerning the personality traits, socioeconomic status, and access to mass communication typical of each adopter category. With a proper understanding of the rate of adoption for the distinct categories, a variety of strategies can be employed to aide in the diffusion of a particular innovation.
While the chapters detailing innovation-development and innovation-decision comprise a comprehensive theoretical construct, the chapters describing diffusion networks and change agents are intensely practical. Contained within these chapters are concepts such as opinion leadership, "the degree to which an individual is able informally to influence other individuals' attitudes or overt behavior in a desired way" (p. 300). Opinion leaders are gatekeepers to social networks. Rogers explains that opinion leadership is the cause for the exponential growth of the innovation curve, as opinion leaders are often the first to spread the message of an innovation to their followers, commonly the early adopters. The business implication of this reality means that in order to spread the word concerning a product or message, the highest leverage first step is to motivate the opinion leaders. The discussion of diffusion networks also illuminates the characteristics of successful dissemination, including the utilitarian differences between heterophily and homophily within networks and the communication structure of interpersonal networks.
Change agents are those people working on behalf of change agencies to bring about a desired change. For readers who sought out this source to discover ways they can implement change, they are seeking to be change agents. Therefore, this chapter is perhaps the most practical chapter in the book. A proper explanation of the underlying realities facing change agents and their targeted audiences provided in this chapter serves as the missing companion in other business books concerning change initiatives such as Leading Change (Kotter, 1996) which heavily favors the day-to-day interactions between agents and their audiences.
Diffusion of Innovation is a comprehensive synthesis of diffusion research and theory. The depth of the research allows Rogers to describe innovation from a variety of viewpoints including adopters, change agents, opinion leaders, and organizations. In one sense, the depth of research is a definite strength of the work. In another sense, however, the breadth of topics and explanation could be overwhelming to the non-academic reader. In the pursuit of comprehensiveness, Rogers investigates tangents in the vein of thoroughness that academia appreciates but that the average reader would consider unnecessary. For example, Rogers devotes two pages to the "inauthentic professionalization of aides" (p. 386-387), and devotes an entire chapter to the history of diffusion research with an additional chapter on the criticisms of diffusion research. Therefore the reader is more than 135 pages into the book before they encounter a probable subject of interest: how innovations develop.
While late-majority and laggard adopters are discussed in comparison to their more innovative counterparts, Rogers does not devote enough time to the reasons for change-resistant networks and the possible hesitancy or fears present in change-resistant people. However, Rogers does dwell on the subject long enough to make an important observation regarding the innovativeness/needs paradox. Given the frequency with which change agencies follow a segmentation strategy based on least resistance, the individuals most needing the benefits of an innovation also tend to be the last to adopt an innovation. Those who are most adoptive--because of the resources, skills, and exposure needed for adoption--generally need the benefits of the innovation the least. The result of the paradox is a widening of the socioeconomic standards gap between the two groups, lending to a reinforcing systems loop, and a continuation of the paradoxical cycle. Rogers correctly points out that if change agencies were to adopt a segmentation strategy of greatest resistance, the reinforcing systems loop would not continue. However, such a strategy is theoretically correct but practically difficult, and Rogers neglects to illuminate why change agencies commonly choose a least-resistance strategy.
Diffusion of Innovation is first and foremost a textbook on diffusion. Though written from an academic perspective, the conceptual framework presented by Rogers since the first edition of this book in 1962 has helped this work to remain a required shelf reference for sociologists, marketers, and change agents for five decades. Despite the exhaustive research foundation of the book, Diffusion of Innovation is still a practical help to leaders concerned with driving change. Business leaders are commonly exposed to the concept of the innovation curve and the adopter categories apart from the context of Rogers' work. In this way, Rogers has added terms to the common business vernacular, and it would behoove leaders to read Diffusion of Innovation to discover the breadth of knowledge accompanying terms so frequently mentioned in boardrooms and team meetings.
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