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Evidence Based Medicine

Evidence-based medicine (EBM) or Evidence-Based Practice (EBP) is the process of systematically reviewing, appraising, and using clinical research findings to support the delivery of clinical care to patients. The basic principle of EBM is that medical professionals should treat where there is evidence of benefit and not treat where there is evidence of no benefit.  According to Dr. David Sacket, a pioneer in the practice and application of EPB, EPB defined is “the conscientious, explicit and judicious use of current best evidence in making decisions about the care of the individual patient.”

The practice of EBP is based primarily upon the following three components:

  • Research Evidence- clinically relevant research from both the basic sciences of medicine and from patient centered clinical research into the accuracy of diagnostic tests (including the clinical examination), the strength of prognostic markers, and the efficacy and safety of therapeutic, rehabilitative, and preventive regimens. New evidence from clinical research replaces previously accepted diagnostic tests and treatments with new ones that are more precise and accurate.
  • Clinical Expertise- the ability to use clinical skills and past experience to rapidly identify each patient’s unique health state and diagnosis, their individual risks and benefits of potential interventions, and their personal values and expectations.
  • Patient Values- the individual preferences, concerns and expectations each patient brings to a medical or clinical encounter and which must be integrated into clinical decisions in order to best meet the patient’s needs.

The integration and combination of these factors enable and empower clinicians and patients to form a mutual alliance which optimizes clinical outcomes and quality of life.



Although the formal assessment of medical interventions using controlled trials was well established in the 1940s, it was not until 1972 that Professor Archie Cochrane, director of the Medical Research Council Epidemiology Research Unit in Cardiff, expressed what later came to be known as evidence-based medicine (EBM) in his book Effectiveness and Efficiency: Random Reflections on Health Services. In the late 1980s and early 1990s, Cochrane’s ideas were developed into a practical methodology by medical groups led by David Eddy at Duke University in North Carolina and Gordan Guyatt and David Sacket at McMaster University in Toronto. In 1992, the United Kingdom government funded the establishment of the Cochrane Center in Oxford under Iain Chalmers. The goal of this Center was to facilitate the preparation of systematic reviews of randomized and controlled trials of healthcare. The following year the Center expanded into an international collaboration of 13 different centers, whose goal is coordinate the activities of 11,500 researchers. The establishment of the Cochrane Collaboration is widely regarded as one of the critical factors in spreading the concept of EBM worldwide.


Practice and Methods

The general practice of EBM comprises five steps which all clinicians must take in order to be facilitate the process.

  • Step 1: Clinicians work in order to convert the need for information (regarding prevention, diagnosis, prognosis, therapy, causation, etc) into an answerable question.
  • Step 2: Clinicians seek to assemble the best and most up-to-date evidence with which to answer that question.
  • Step 3: Clinicians appraise and assess the evidence for its validity (truthfulness), impact (size of the effect), and applicability (usefulness to the specific clinical practice and situation).
  • Step 4: Clinicians integrate the critical appraisal with clinical expertise and with the patient’s unique biology, values, and circumstances.
  • Step 5: Clinicians evaluate effectiveness and efficiency in executing Steps 1-4. Clinicians also seek ways to improve methods for next clinical encounter.


Uses and Implementations

Evidence-based medicine and practices have been used and continue to be widely available for a number of conditions such as asthma, heart failure, and diabetes. In addition, this practice has also been used in educating children with autism. The nursing profession has a rich history of using research in practice, a concept first pioneered by Florence Nightingale. Although during the early and mid-1900s few nurses applied Nightingale’s approach, the nursing profession has more recently provided major leadership for improving care through application of research findings in practice.


Limitations and Criticisms

The examination of the methodology of EBM by clinicians and academics has produced mixed results. The debate has identified three limitations that are unique to EBM. The constant need to develop new skills in searching and critical appraisal is challenging and time-consuming, but true Evidence-Based care may only be applied these skills have been mastered. Additionally, busy clinicians have limited time to learn, master and integrate these new skills, and often the resources required for instant access to research and evidence are inadequate in clinical settings. Finally, discernible evidence that EBM is a practice and methodology which “truly works” has yet to emerge as a medically accepted and established practice.


Additional Resources

Centre for Evidence-Based Medicine (Oxford University)-The Centre promotes evidence-based health care and provide support and resources to anyone who wants to make use of them.

Evidence-Based Medicine Tutorial-This comprehensive and informative tutorial is put together by State University of New York (SUNY) Medical Center.

Introduction to Evidence-Based Medicine- Compiled by Duke University Medical Center Library and University of North Carolina at Chapel Hill Health Sciences Library, this comprehensive guide to Evidence-Based Medicine covers a variety of educational and research related topics.

Users’ Guides to Evidence-Based Practice-From the University of Alberta’s Center for Health Evidence. This resource includes the complete set of EBM Users’ Guides originally published as a series in the Journal of the American Medical Association (JAMA).