Two qualitative studies in the U.K. health care sector trace eight purposefully selected innovations. Complex, contested, and nonlinear innovation careers emerged. Developing the nonlinear perspective on innovation spread further, we theorize that multiprofessionalization shapes "nonspread." Social and cognitive boundaries between different professions retard spread, as individual professionals operate within unidisciplinary communities of practice. This new theory helps explain barriers to the spread of innovation in multiprofessional organizations in both health care and other settings. I think all the evidence about innovation in general practice points to the fact that rarely, very rarely, does a single method change people's behaviour.

This article aims to provide a reassessment of the processes of diffusion of innovations into organizations, based on new empirical data. The focus of the article is the latter stages of the diffusion process. The article draws on the results of two studies, which examined the diffusion of innovations in health care in the UK. These projects were a matched pair of qualitative studies, using purposeful selections of comparative case studies. The results demonstrate the ambiguous, contested nature of new scientific knowledge. The highly interactive nature of diffusion, with active adopters is illustrated. There is no evidence of a single adoption decision. The science is socially mediated. The features of context and of actors interlock to influence diffusion.