1. LECTURE 13 The Diffusion of Innovations 1

2. What is Diffusion of Innovation?  It is not so much about what researchers or inventors innovate– it is more about what people adopt. 2

3. Definition of Diffusion of Innovation  “the process by which an innovation is communicated through certain channels over time among the members of a social system” (Rogers 1983) 3

4. Four Basic Concepts in Diffusion of Innovation  Innovation  Idea, object, or practice that is perceived as new  Channels of Communication  Means by which info is transmitted to or within the social system  Time  Rate at which the innovation is diffused or the relative speed with which it is adopted  Social System  Individuals, organizations, or agencies that are potential adopters of the innovation 4

5. Common Scope of Diffusion Research  (1) Characteristics of an innovation which may influence its adoption  (2) Decision-making process that occurs when individuals consider adopting a new innovation  (3) The characteristics of individuals that make them likely to adopt the innovation  (4) The consequences for individuals and society of adopting the innovation  (5) Communication channels used in the adoption process 5

6. Various Early Diffusion Studies 6 InvestigatorInnovation Social System Rapoport (1978) Radioisotopes U.S. Hospitals Perry and Kraemer (1978) Computer Applications Local Govt Pitcher et al. (1978) Collective violence Countries Oster (1982) Basic oxygen furnace Steel manufacturers Adapted from Mahajan and Peterson (1985)

7. Purpose of Diffusion Models  To depict the successive increase in the number of adopters over time.  Permits prediction of the continued development of the diffusion process.  Facilitates a theoretical explanation of the dynamics of the diffusion process. 7

8. Who uses this stuff?  Marketers!  Movie studios  Political and Interest groups 8

9. Foundations of Research on Diffusion of Innovations  Gabriel Tarde (1903)  Proposed the S-shaped curve  As it turned out, study after study tended to show the exact same S-shaped curve when researchers plot the rate of adoption over time. 9

10. Diffusion “S” Curve 10

11. Foundations of Research on Diffusion of Innovations  Ryan and Gross (1943)  Categories of Adopters (relative time of adoption) Innovators Early adopters Early/Late Majorities Laggards 11

12. Opinion Leadership  Opinion leaders are key for influence and thus ability to successfully diffuse an innovation.  Opinion leaders are concentrated among the early adopters, not the innovators. 12

13. Adopter Categories 13

14. Stages of Adoption  Everett Rogers (1995)  Awareness  Interest  Evaluation  Trial  Adoption 14

15. Categorizing Adopters and Non-Adopters  Adoption:  accept and use innovation  Nonadoption:  nontrial of an innovation  Discontinuance:  rejection of an innovation after it has previously been adopted 15

16. Epidemic Models  Based on simple examination of “spread”  Simplest version is basic exponential model  Central-source model 16 N of users Time

17. Epidemic Models (continued)  Modified spread model  Diffusion works through word-of-mouth (i.e., previous users) 17 N of users Time