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Evidence-based medicine: tools not rules
  1. Philip Wiffen
  1. Correspondence to Philip Wiffen, Cochrane Pain, Palliative and Supportive Care Group, Churchill Hospital, Oxford OX3 7LE, UK; phil.wiffen{at}


Evidence-based medicine (EBM) has been influencing medicine for almost 20 years. It is important because the volume of medical literature available means it is impossible to stay up to date. This article looks at the background and definitions of EBM together with an outline of the tools that can support EBM in practice. Methods of grading the reliability of published articles are discussed. The role of systematic reviews and the utility of forest plots, L'Abbe plots and numbers needed to treat are presented. Some see EBM as a rule book whereas its strengths are in the ability to give tools to assess evidence. While evidence is primarily used for individual patient care, it can also be used for professional interventions and changing systems. Clinical pharmacists are encouraged to develop these skills in their clinical practice.

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