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Evidence Based Medicine Guide: Introduction

EBM: Since 1992

did you know

The term "evidence-based medicine" first appeared in the medical literature in 1992 in a paper by Gordon Guyatt and others on an Evidence-Based Medicine Working Group (1).

(1) Howick, JH. The Philosophy of Evidence-Based Medicine. Chichester, West Sussex, UK: Wiley-Blackwell, BMJ Books, 2011.


Although Evidence Based Medicine (also known as Evidence Based Practice) is a complex practice involving several careful steps, its core principle is simple: decisions about patient care should be informed by the best available research data. Patient values and preferences, clinician expertise and the patient's clinical state and circumstances are also accounted for in the EBM model. Because the emphasis in EBM is on translating the best evidence from the research literature into clinical practice, efficient literature searching and application of formal rules of evidence in appraising research findings comprise core skills of EBM practice1.

Goals and Objectives


The goals of this tutorial are to clearly outline the theory of evidence based medicine and to explain how that theory can be put to practice in the day-to-day work of caring for patients. 


The "5A's Cycle" of EBM includes assessing the patient and prioritizing questions about his/her care, asking a focused clinical question, acquiring the evidence to answer the question, appraising the research and applying the research findings to patient care. The cycle begins again with an assessment of the patient and the patient's care2

The tutorial is focused primarily on the second and third steps of the Evidence Cycle: asking questions and acquiring the best evidence.  In particular, it suggests specific strategies for finding evidence from primary studies, systematic reviews and meta-analyses using tools currently available in PubMed's MEDLINE interface.  Appraisal is briefly touched upon, with suggestions for scanning search results to identify articles more likely to yield robust, applicable evidence. 

By the end of this tutorial, you should be able to:

  • Formulate a clinical question using the PICO framework;
  • Identify five common categories of clinical questions;
  • Identify which research methodologies provide the best evidence for your question type;
  • Distinguish between systematic reviews, meta-analyses and narrative or clinical topic reviews;
  • Search Medline/PubMed effectively for studies likely to provide the current best evidence by
    • Identifying appropriate search terms, including Medical Subject Headings (MeSH) terms; and
    • Employ evidence filters such as PubMed's Clinical Queries;
  • Identify articles from your PubMed search results that are most likely to provide current, valid, reliable and relevant evidence to answer your question.

This tutorial assumes you already have some familiarity with basic and advanced PubMed search techniques, as well as with MeSH searching.

There are many excellent online and print guides that address the critical appraisal of a research report and the application of evidence to an individual patient's care. You will find links to selected resources that provide especially rich content in these areas in the Appraise and Apply modules of this tutorial.


(1) Guyatt G, Cairns J, Churchill D, et al. Evidence-Based Medicine: A New Approach to Teaching the Practice of Medicine. JAMA. 1992;268(17):2420-2425. doi:10.1001/jama.1992.03490170092032

(2) Guyatt G, Rennie D, Meade MO, Cook DL. Users' Guides to the Medical Literature: A Manual for Evidence-Based Clinical Practice. 2nd ed. New York: NY: McGraw-Hill Education; 2008.