Intended for healthcare professionals


What's the E for EBM?

BMJ 2004; 328 doi: (Published 04 March 2004) Cite this as: BMJ 2004;328:535
  1. Sharon E Straus (sstraus{at}, assistant professor
  1. Toronto General Hospital, 200 Elizabeth Street, Toronto, Canada M5G 2C4

    Theme issue will question the evidence for evidence based medicine

    Interest in evidence based medicine has grown exponentially from one Medline citation in 1992 to more than 13 000 in 2004. Professional organisations and training programmes for healthcare professionals have moved from whether to teach evidence based medicine to how to teach it, resulting in an explosion in the number of courses, workshops, and seminars offered in this practice. Reports describing evidence based rejuvenations of traditional educational events are burgeoning, and case reports and a survey of residency programmes have concluded that some of the determinants of continuing high attendance at postgraduate journal clubs include the teaching of critical appraisal skills and emphasising the primary literature (and not surprisingly, providing free food).1 2 Familiarity with its terminology has extended into the popular press, as evidenced by a recent article in the Times describing the number needed to treat.3 But all this leads to the question, “What's the E for EBM?”

    Discussion about the practice of evidence based medicine naturally engenders negative and positive reactions from clinicians. Some of the criticisms focus on misunderstandings and misperceptions of evidence based medicine such as the concerns that it ignores patients' values and preferences and promotes a cookbook approach.4 But this debate has highlighted limitations unique to the practice of evidence based medicine that must be considered. For example, the difficulty of developing new skills in seeking and appraising evidence cannot be underestimated. Moreover, the need to develop and apply these skills within the time constraints of our clinical practice must be addressed.

    The body of evidence relating to the impact of evidence based medicine on healthcare professionals ranges from systematic reviews of training in the skills of evidence based medicine to qualitative research describing the experience of evidence based medicine practitioners.5 6 However, studies of the effect of teaching and practising evidence based medicine are challenging to conduct. In many studies, the intervention has been difficult to define. What the appropriate “dose” or “formulation” should be is unclear. Some studies use an approach to clinical practice while others use training in one of the discrete microskills of evidence based medicine such as searching Medline or critical appraisal.5 7 Moreover, learners have different learning needs and styles, and these differences must be reflected in the educational experiences provided.

    Just as the intervention has proved difficult to define, its evaluation has been challenging. Effective interventions involving evidence based medicine produce a wide range of outcomes. Changes in knowledge and skills are relatively easy to detect and demonstrate. Changes in attitudes and behaviours are harder to confirm. Still more challenging is detecting changes in clinical outcomes.

    By questioning the evidence for evidence based medicine are we asking the right question? Providing evidence from clinical research is a necessary but not sufficient condition for the provision of optimal care. This has created interest in knowledge translation—the scientific study of the methods for closing the gap between knowledge and practice—and the analysis of barriers and facilitators inherent in this process.8 Proponents of knowledge translation have identified that changing behaviour is a complex process requiring comprehensive approaches directed towards patients, doctors, managers, and policy makers, and providing evidence is but one component.9 Moreover, it may be too soon to tell if evidence based medicine changes clinical performance and outcomes because advocates think that it requires lifelong learning, and this is not something that can be measured over the short term.

    The BMJ will publish a theme issue on “What's the evidence that evidence based medicine changes anything?” in October 2004. We see this as an opportunity to reflect on the challenges of practising and teaching evidence based medicine, highlighting the work that has been done in this field and providing an opportunity to point the way forward. We invite contributions from researchers, patients, health professionals, policy makers, and other stakeholders, to reach us by 15 April 2004. Submissions should be made to, and the editorial contact is Giselle Jones (gjones{at}


    • SES is funded by a Career Award from the Ministry of Health and Long-term Care, and from the Knowledge Translation Program at the University of Toronto.

    • Competing interests SES is an associate editor of the journal EBM and ACP Journal Club.