Objectives: To study the relationship between research evidence and clinical behaviour change in the UK National Health Service (NHS) in the period 1995-1997 by examining the 'careers' of change issues designed to reshape clinical practice, the impact of such change efforts, and the factors shaping change outcomes.
Methods: Comparative case study methods were used. Four clinical change issues were studied using semi-structured interviews (n = 119) and documentary analysis in one English NHS region. For each issue, there was an overview semi-structured interview survey of the issue at regional level, followed by an intensive analysis of its impact at local level on the practice of specific clinical groups.
Results: There was a weak relationship between the evidence base and its diffusion. The diffusion and take-up of scientific evidence were shown to be socially constructed. Different forms of evidence were differentially accepted by individuals and groups. Specific organisational and social factors affected this pattern of impact. The general management hierarchy of the NHS played a very limited role in enabling evidence-based clinical change.
Conclusions: The implementation of evidence-based medicine is a complex and contested process. The results of this study confirm a professional dominance model of clinical behaviour change and identify tacit expert knowledge as a key power resource in shaping the way research evidence influences clinical practice.