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Evidence Based Medicine (EBM) - NJMS

EBM Background

David Sackett led the first of what became the Evidence-based health care workshop in McMaster University in 1982. One of his mentees, Gordon Guyatt introduced the term "Evidence-based medicine" in 1990.

This article was written in 2015 in memory of Dr. David Sackett. 

Thoma, A., & Eaves, F. F. (2015). A Brief History of Evidence-Based Medicine (EBM) and the Contributions of Dr David Sackett. Aesthetic surgery journal, 35(8), 261-263.

EBM Definition

In the 1990s, a team of medical professionals from Oxford, McMaster, Duke and other medical universities, led by David Sackett of McMaster University defined evidence-based medicine (EBM), also known as evidence-based health care (EBHC) and evidence-based practice (EBP).

They published an article, in the article they defined "Evidence based medicine is the conscientious, explicit and judicious use of current best evidence in making decisions about the care of individual patients.” - Sackett et al., 1996

As the area has evolved, a new definition was given, “Evidence-based medicine (EBM) requires the integration of the best research evidence with our clinical expertise and our patient’s unique values and circumstances.” - Straus et al., 2019

Masic et al. articulates that the key difference between evidence-based medicine and traditional medicine is not that EBM considers the evidence while the latter does not. Both take evidence into account; however, EBM demands better evidence than has traditionally been used. In the original EBM article written by Dr. Sackett, he states that “studies show that busy clinicians who devote their scarce reading time to selective, efficient, patient driven searching, appraisal, and incorporation of the best available evidence can practice evidence based medicine”. So some key steps in practicing EBM are to find current best evidence and appraise the evidence. 

David L. Sackett, William M. C. Rosenberg, J. A. Muir Gray, R. Brian Haynes, & W. Scott Richardson. (1996). Evidence Based Medicine: What It Is And What It Isn’t: It’s About Integrating Individual Clinical Expertise And The Best External Evidence. BMJ: British Medical Journal, 312(7023), 71–72.

Straus, Glasziou, P., Richardson, W., & Haynes, R. (2019). Evidence-Based Medicine : How to Practice and Teach EBM (5th ed.). Elsevier Health Sciences.

Masic, Miokovic, M., & Muhamedagic, B. (2008). Evidence based medicine - new approaches and challenges. Acta Informatica Medica16(4), 219–225.

EBM Steps

Evidence Based Medicine is a patient-centered care. It is also well known for the 5 A’s of EBP cycle:

Step 1: ask a searchable question

Converting the need for information (about prevention, diagnosis, prognosis, therapy, causation, etc.) into an answerable question.

Step 2: acquire information

Tracking down the best evidence with which to answer that question.

Step 3: appraise search results

Examining research studies to judge its credibility, its value and its relevance in a specific context.

Step 4: apply the evidence in practice

Integrating the critical appraisal with our clinical expertise and with our patient’s unique biology, values, and circumstances.

Step 5: assess the provided care

Evaluating our effectiveness and efficiency in executing steps 1 to 4 and seeking ways to improve them both for next time.

This research guide focuses on step 1-3. 

Levels of evidence

Adapted from EBM Pyramid © 2006 Trustees of Dartmouth College and Yale University.

One way to organize the different types of evidence involved in evidence-based practice research is the levels of evidence pyramid. The pyramid includes a variety of evidence types and levels. The pyramid serves as a guideline to the hierarchy of study design. One may not always find the highest level of study to answer your question. The quality of the evidence is also important. 

Articles about study design:

Grimes, & Schulz, K. F. (2002). An overview of clinical research: the lay of the land. The Lancet (British Edition), 359(9300), 57–61.

Clarke. (1998). Ovarian ablation in breast cancer, 1896 to 1998: milestones along hierarchy of evidence from case report to Cochrane review. BMJ317(7167), 1246–1283.

Study designs by CEBM


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