Social work theory · Volume F: Community, Collective & Social Change

Diffusion of innovations

Diffusion of innovations theory explains how new ideas, practices and technologies spread through a social system over time.

1. What it is

Diffusion of innovations theory explains how new ideas, practices and technologies spread through a social system over time. Everett Rogers (2003) defined diffusion as the process by which an innovation is communicated through certain channels over time among the members of a social system. An innovation is any idea, practice or object that people perceive as new, regardless of how long it has existed. The theory identifies four main elements: the innovation, communication channels, time, and the social system in which adoption occurs. For social work, it explains why some evidence-based programs and practice reforms spread quickly while others are adopted slowly or not at all, and it provides a foundation for implementation science (Dearing, 2009; Greenhalgh et al., 2004).

Everett Rogers’ theory. Rogers first published Diffusion of Innovations in 1962, synthesising studies from rural sociology, education, medicine and marketing. He described the innovation-decision process as five stages that an individual or organisation passes through: knowledge, persuasion, decision, implementation and confirmation (Rogers, 2003). Mass media are most effective at creating awareness, while interpersonal communication with similar peers is most influential in persuading people to adopt. Adoption over time typically follows an S-shaped curve: slow at first, accelerating as more people adopt, and then levelling off.

Adopter categories. Rogers (2003) classified members of a social system by how early they adopt an innovation. Innovators (about 2.5 per cent) are venturesome and connected to outside networks. Early adopters (13.5 per cent) are respected opinion leaders whose example influences others. The early majority (34 per cent) adopt after deliberation, and the late majority (34 per cent) adopt cautiously, often because of economic or social pressure. Laggards (16 per cent) are the last to adopt and are oriented to tradition. These percentages derive from a normal distribution and are ideal types. Rogers later acknowledged that the label “laggard” can blame individuals for structural barriers such as lack of resources.

Attributes of innovations. Rogers (2003) identified five perceived attributes that explain much of the variation in adoption rates. Relative advantage is the degree to which an innovation is seen as better than what it replaces. Compatibility is consistency with existing values, experience and needs. Complexity is how difficult the innovation is to understand and use. Trialability is the extent to which it can be tested on a limited basis. Observability is the degree to which its results are visible to others. Innovations that are advantageous, compatible, simple, trialable and observable spread faster.

Opinion leaders, change agents and re-invention. Diffusion depends on social networks. Opinion leaders informally influence others’ attitudes, and change agents are professionals who try to influence adoption decisions on behalf of an agency (Rogers, 2003). Re-invention is the degree to which users change an innovation during adoption. Rogers found that re-invention often increases adoption and sustainability, although it can reduce fidelity to an evidence-based model.

Links to implementation science. Implementation science studies methods for promoting the systematic uptake of research findings into routine practice (Eccles & Mittman, 2006). Greenhalgh et al. (2004) conducted a major systematic review of diffusion in health service organisations. They extended Rogers’ individual-focused model to organisations, showing that adoption depends on the innovation, the adopters, communication and influence, the system’s readiness and absorptive capacity, the outer context, and the implementation process. They distinguished passive diffusion, active dissemination and planned implementation. Later frameworks, such as the Consolidated Framework for Implementation Research, built on this review (Damschroder et al., 2009).

2. Historical development

Early accounts of the spread of ideas through imitation date from Tarde (1890/1903), but systematic diffusion research began in rural sociology. Ryan and Gross (1943) showed that Iowa farmers adopted hybrid seed corn gradually, with neighbours and peers more influential than salespeople or advertising. Similar patterns appeared in studies of education, medicine and public health. Rogers integrated these separate research traditions into a single general theory, establishing diffusion of innovations as an independent field of communication research (Rogers, 2003).

Social work and human services took up diffusion theory as policy makers began to promote evidence-based programs. The gap between research evidence and routine practice led to interest in why proven interventions were not used. Dearing (2009) argued that social work interventions should be designed from the start with diffusion in mind. Implementation science, drawing directly on Rogers and Greenhalgh et al. (2004), now informs how agencies introduce new programs in child welfare, mental health and family services (Aarons et al., 2011).

3. Practical guidance

Diffusion theory helps social workers and managers introduce new practices in ways that increase uptake and sustainability.

• Assess the innovation’s attributes. Before introducing a new program or tool, ask whether staff will see a clear advantage, whether it fits agency values and practice, and how complex it is (Rogers, 2003).
• Allow trial and make results visible. Pilot new practices in one team, then share outcomes through case examples and data so that others can see the results.
• Engage opinion leaders. Identify respected practitioners who can model and champion the change. Peer influence is often more persuasive than management direction.
• Fit the innovation to context. Adapt programs for local populations, including culturally safe adaptations for Aboriginal and Torres Strait Islander communities, while protecting the core components that make them effective.
• Assess organisational readiness. Consider leadership support, staff capacity, supervision and resources before implementation (Greenhalgh et al., 2004).
• Plan for implementation as well as dissemination. Training alone rarely changes practice. Combine training with coaching, supervision and monitoring of fidelity (Aarons et al., 2011).
• Attend to equity in adoption. Groups and services with fewer resources may adopt later because of structural barriers, so target support where uptake is slowest.

4. Critical evaluation

Strengths. Diffusion of innovations is one of the most extensively researched theories in the social sciences, with thousands of studies across many fields (Rogers, 2003). Its concepts are intuitive and easy to apply in practice settings. The attributes of innovations and the role of opinion leaders give practitioners concrete levers for planning change. Its extension to organisations by Greenhalgh et al. (2004) has made it central to implementation science.

Limitations. Rogers himself identified a pro-innovation bias, the assumption that innovations should be adopted by everyone, which can obscure cases where rejection is rational or where innovations cause harm. The individual-blame bias attributes slow adoption to people’s characteristics and neglects structural barriers such as poverty and lack of infrastructure. Classical diffusion research focused on individual adoption and gave less attention to organisations and complex social interventions (Greenhalgh et al., 2004). In human services, adoption of a program does not guarantee that it is implemented well or sustained.

Overall importance. Diffusion of innovations theory explains how new knowledge moves into practice. It underpins much of contemporary implementation science and offers social workers practical guidance for introducing evidence-informed programs. It links closely to organisational change (F7) and to evidence-informed practice (G7).

5. References

• Aarons, G. A., Hurlburt, M., & Horwitz, S. M. (2011). Advancing a conceptual model of evidence-based practice implementation in public service sectors. Administration and Policy in Mental Health and Mental Health Services Research, 38(1), 4–23. https://doi.org/10.1007/s10488-010-0327-7
• Coleman, J. S., Katz, E., & Menzel, H. (1966). Medical innovation: A diffusion study. Bobbs-Merrill.
• Damschroder, L. J., Aron, D. C., Keith, R. E., Kirsh, S. R., Alexander, J. A., & Lowery, J. C. (2009). Fostering implementation of health services research findings into practice: A consolidated framework for advancing implementation science. Implementation Science, 4, Article 50. https://doi.org/10.1186/1748-5908-4-50
• Dearing, J. W. (2009). Applying diffusion of innovation theory to intervention development. Research on Social Work Practice, 19(5), 503–518. https://doi.org/10.1177/1049731509335569
• Eccles, M. P., & Mittman, B. S. (2006). Welcome to Implementation Science. Implementation Science, 1, Article 1. https://doi.org/10.1186/1748-5908-1-1
• Greenhalgh, T., Robert, G., Macfarlane, F., Bate, P., & Kyriakidou, O. (2004). Diffusion of innovations in service organizations: Systematic review and recommendations. The Milbank Quarterly, 82(4), 581–629. https://doi.org/10.1111/j.0887-378X.2004.00325.x
• Rogers, E. M. (2003). Diffusion of innovations (5th ed.). Free Press.
• Ryan, B., & Gross, N. C. (1943). The diffusion of hybrid seed corn in two Iowa communities. Rural Sociology, 8(1), 15–24.
• Tarde, G. (1903). The laws of imitation (E. C. Parsons, Trans.). Henry Holt. (Original work published 1890)