This concluding chapter aims to address what factors and mechanisms explain the differences between the development of evidence-based guidelines. The conclusions drawn from this study will be organised around the themes identified in the sub-questions of this book: What role does evidence play in creating differences and similarities in guidelines and what types of ‘evidence’ are used? How do institutional framings impact on guideline development? What is the role of group decision-making in the development of guidelines? What is the role of evidence on cost and cost-effectiveness in the formation of guidelines? How do external factors determine choices made in guideline development? And finally, how do these factors and mechanisms impact on guidelines as a form of professional self-regulation?

EVIDENCE

Evidence has been of central concern in this book. To study empirically how guideline groups, grapple with the fact that guidelines must be evidence-based has been a key theme in understanding the development of medical practice guidelines.

It turns out guidelines are not based on evidence in a straightforward sense; rather they are the result of a complex negotiation of social, economic, political and normative mechanisms that both select and shape evidence in various ways. The notion of cognitive framing turns out to be a powerful conceptual tool to describe this black box in detail.

A major conclusion of this book is that evidence-based guidelines are not as evidence-based as they claim to be; rather, the term ‘evidence-based guideline’ is used to justify subjective normative and political choices in professional self-regulation. This allows for a new understanding of how scientists construct and produce knowledge and how this is consequently presented as empirical truth. The analysis suggests that guidelines are an expression of a temporal closure of debate on the optimal medical choices regarding a specific condition.

This process of selecting evidence and evaluating the methodological soundness of evidence is relatively well understood. It has been shown how different guideline groups make different decisions. Some only include evidence of a certain quality (RCTs), others rely on summaries of studies (Cochrane Reviews One could stop there and consider that because guideline groups differ in their process of selecting evidence, this explains the differences in the development of guidelines. This is where existing scholarship is lacking as it fails to consider how this evidence is then used in a social and constructive process to make recommendations in a guideline.