Evidence Based Medicine


  • Sackett originally defined EBM as the conscientious and judicious used of current best evidence from clinical research in the management of individual patients
  • Evidence-based medicine is the process of systematically reviewing, appraising and using clinical research findings to aid the delivery of optimal clinical care to patients.
    It involves considering research and other forms of evidence on a routine basis when making healthcare decisions. Such decisions include the clinical decisions about choice of treatment, test, or risk management for individual patients, as well as policy decisions for groups and populations.
  • There are >2,000,000 papers published each year, but our patients only benefit from a tiny fraction of these papers


Five steps of evidence-based practice

1. Translation of uncertainty to an answerable question (ask question)
2. Systematic retrieval of best evidence available (find evidence)
3. Critical appraisal of evidence for validity, clinical relevance, and applicability (critically appraise)
4. Application of results in practice (make clinical decisions)
5. Evaluation of performance (audit)



  • our reading habits and critical appraisal skills improve
  • it leads us to ask questions and be more sceptical of the answers
  • wasteful practices can be abandoned
  • presupposes that we keep up-to-date
  • makes the decision-making process transparent to colleagues and patients
  • leads to greater appreciation of the evidence for our practice, and the inherent uncertainties

Disadvantages of EBM

  • time-consuming
  • expensive
  • sometimes impossible (when there is no published literature on a question)
  • useful papers may be disregarded because of minor blemishes (‘rescue bias’)
  • there is no science to tell us how robust evidence needs to be for use to incorporated into clinical practice
  • external validity is subjective and evidence can be mis-applied
  • easy-to-prove techniques more favored in literature
  • it is never ‘up-to-date’
  • tends to emphasise the priority of RCTs (which have inherent flaws) to the exclusion of other study designs (which may be appropriate in certain settings)
  • may under emphasise patient values and interests


A good question follows the PICO format and includes:

1.    the patient or problem being addressed
2.    the intervention or exposure being considered
3.    the comparison intervention or exposure, when relevant
4.    the clinical outcomes of interest

References and Links

  • Dawes M, Summerskill W, Glasziou P, Cartabellotta A, Martin J, Hopayian K, Porzsolt F, Burls A, Osborne J; Second International Conference of Evidence-Based Health Care Teachers and Developers. Sicily statement on evidence-based practice. BMC Med Educ. 2005 Jan 5;5(1):1. Review. PubMed PMID: 15634359; PubMed Central PMCID: PMC544887.
  • Sackett DL, Rosenberg WM, Gray JA, Haynes RB, Richardson WS. Evidence based medicine: what it is and what it isn’t. BMJ. 1996 Jan 13;312(7023):71-2. PubMed PMID: 8555924; PubMed Central PMCID: PMC2349778.
  • CEM — What is EBM?
  • http://jama.jamanetwork.com/article.aspx?articleid=1676494
  • http://update.anaesthesiologists.org/2012/12/21/evidence-based-medicine-in-critical-care-update-28-2012/
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