In practice, we seek to use the best evidence to underpin our decisions. That evidence is likely to be a mix of robust research evidence, clinical experience, patient preferences and experiences, and local information 1 So research is an important part, but not the only part, of your decision about care.

Although there is much talk about evidence-based policy, research evidence has to compete with a range of additional factors that influence decisions about what will become policy. These factors may include experience, expertise, judgement, values, resources, habits and traditions.2 In addition, The Economist3 commented ‘the ambiguities of science sit uncomfortably with the demands of politics. Politicians, and the voters who elect them, are more comfortably with certainty.’ p13. Krebs4 discusses the relationship between scientific evidence, uncertainty and …