This book is a socio-legal enquiry into the development of medical practice guidelines that provides insights into professional self-regulation and the ‘black box’ of guideline making. We all would like to receive the best medical care possible. When we see our general practitioner (GP) we expect to receive the best possible care, independent of location.

In response to increasing calls for the accountability of medical professionals, consensus-based medical practice guidelines were developed in the latter part of the 1970s in the United States of America and quickly spread to the Netherlands and England. The aim of these guidelines was to reduce practice variation by achieving consensus among a large group of medical professionals on the best care for medical conditions. If guidelines would be widely followed, treatments would, in principle, have to be the same.

However, in the 1990s, the fact that these guidelines were developed on the basis of consensus among experts was questioned and there was a call to base guidelines on a systematic appraisal of all available scientific evidence: one that would provide universal knowledge on which to base medical decisions. This ‘evidence-based medicine’ movement had a profound effect on the medical world and is suggested by some to be one of the most important developments in modern medicine. As a result of this movement, all medical practice guidelines are now described as evidence-based and it is these guidelines that will be considered here.

The motivation here lies in the observation that when comparing evidence-based medical guidelines across countries, the same diseases are often treated in different ways. There is no obvious reason to suspect, for example, that the populations of England and the Netherlands are so different that this could explain these differences. As evidence-based medicine endorses the systematic use of the best available evidence and both countries have access to the same (English-language) medical studies, it would be expected that the guidelines would reflect these similarities? So, the question that follows is how do differences in medical guidelines occur despite access to the same evidence? Or conversely, how is it that some elements are similar between countries despite these guidelines referring to very different evidence to support their recommendations?