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Centre for Evidence-
Based Medicine

Why the sudden interest in EBM?

These ideas have been around for a long time. The authors of this book identify with their expression in post-revolutionary Paris (when clinicians like Pierre Louis rejected the pronouncements of authorities1 and sought the truth in systematic observation of patients), and a colleague has nominated a much earlier origin in ancient Chinese medicine2. In the current era, they were consolidated and named EBM in 1992 by a group led by Gordon Guyatt at McMaster University in Canadai. Since then, the number of articles about evidence-based practice has grown exponentially (from 1 publication in 1992 to about a thousand in 1998) and international interest has led to the development of 6 evidence-based journals (published in up to 6 languages) that summarize the most relevant studies for clinical practice and have a combined world-wide circulation of over 175,000.

The subsequent rapid spread of EBM has arisen from 4 realizations and is made possible by 5 recent developments.

The realizations, attested to by ever-increasing numbers of clinicians, are:

  1. our daily need for valid information about diagnosis, prognosis, therapy and prevention (up to 5 times per in-patientii and twice for every 3 out-patientsiii).
  2. the inadequacy of traditional sources for this information because they are out-of-date (textbooksiv), frequently wrong (expertsv), ineffective (didactic continuing medical educationvi) or too overwhelming in their volume and too variable in their validity for practical clinical use (medical journalsvii).
  3. the disparity between our diagnostic skills and clinical judgement, which increase with experience, and our up-to-date knowledgeviii and clinical performanceix, which decline.
  4. our inability to afford more than a few seconds per patient for finding and assimilating this evidencex, or to set aside more than half an hour per week for general reading and studyxi.

Until recently, these problems were insurmountable for full-time clinicians. However, 5 developments have permitted us to turn this state of affairs around:

  1. the development of strategies for efficiently tracking down and appraising evidence (for its validity and relevance)xii.
  2. the creation of systematic reviews and concise summaries of the effects of health care (epitomized by the Cochrane Collaborationxiii).
  3. the creation of evidence-based journals of secondary publication (that publish the 2% of clinical articles that are both valid and of immediate clinical usexiv).
  4. the creation of information systems for bringing the foregoing to us in seconds.
  5. the identification and application of effective strategies for life-long learning and for improving our clinical performancexv.

This book is devoted to describing these innovations, demonstrating their application to clinical problems, and showing how they can be learned and practiced by clinicians who have just 30 minutes per week to devote to their continuing professional development.


  1. For us, Louis's most dramatic rejection was the authoritarian pronouncement that venesection was good for cholera!
  2. During the reign of Emperor Qianlong, the method of "kaozheng" ("practising evidential research") was used to interpret ancient Confucian texts (Woodhouse, personal communication, 1998).


  1. Evidence-Based Medicine Working Group: Evidence-based medicine. A new approach to teaching the practice of medicine. JAMA. 1992;268: 2420-5
  2. Osheroff JA; Forsythe DE; Buchanan BG; Bankowitz RA;Blumenfeld BH, Miller RA. Physicians' information needs: analysis of questions posed during clinical teaching. Ann Intern Med 1991;114:576-81.
  3. Covell DG, Uman GC, Manning PR: Information needs in office practice: Are they being met? Ann Intern Med 1985;103:596-9.
  4. Antman EM, Lau J, Kupelnick B, Mosteller F, Chalmers TC: A comparison of results of meta-analyses of randomised control trials and recommendations of clinical experts. JAMA 1992;268:240-8.
  5. Oxman A, Guyatt GH: The science of reviewing research. Ann NY Acad Sci 1993;703:125-134
  6. Davis D A, Thomson M A, Oxman A D, Haynes R B: Changing physician performance: a systematic review of the effect of continuing medical education strategies. JAMA 1997;274:700-5.
  7. Haynes RB. Where's the Meat in Clinical Journals [editorial]? ACP Journal Club. 1993 Nov-Dec;119:A-22-3.
  8. Evans CE, Haynes RB, Birkett NJ et al: Does a mailed continuing education program improve clinician performance? Results of a randomised trial in antihypertensive care. JAMA 1986:255:501-4.
  9. Sackett DL, Haynes RB, Taylor DW, Gibson ES, Roberts RS, and Johnson AL. Clinical determinants of the decision to treat primary hypertension. Clinical Research 1977;24:648.
  10. Sackett DL, Straus SE: Finding and applying evidence during clinical rounds: the evidence cart. JAMA. 1998;280:1336-8
  11. Sackett, D L. Using Evidence-Based Medicine to help Physicians keep Up-to-Date. Serials. 1997;9:178-81.
  12. Sackett DL, Richardson WS, Rosenberg W, Haynes RB: Evidence-Based Medicine: How to Practise and Teach EBM. London: Churchill-Livingstone, 1997. Published in English, Spanish, Italian, and Japanese.
  13. The Cochrane Library, Issue 2, 1999. Oxford: Update Software.
  14. At the time of writing, this list comprised (in order of 1st publication) ACP Journal Club, Evidence-Based Medicine, Evidence-Based Health Policy and Management, Evidence-Based Cardiovascular Medicine, Evidence-Based Mental Health, Evidence-Based Nursing, and a growing number of "Best-Evidence" departments in existing journals.
  15. Cochrane Effective Practice and Organisation of Care Group. The Cochrane Library, Issue 2, 1999. Oxford: Update Software.