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Evidence-Based Practice Guide

OCEBM Level of Evidence Table

The OCEBM Levels of Evidence Table (Levels) is a more complex hierarchy of evidence. The Levels allows the clinician to answer a variety of clinical questions, including diagnosis, prognosis, therapy and harms. Greenhalgh (2019) recommends that you understand the traditional (basic) hierarchy described in Chapter 3 of How to Read a Paper: the basics of evidence based medicine, 6th ed, before you access the Levels.

The 2011 OCEMB Levels of Evidence is:

  1. A hierarchy of the likely best evidence.
  2. Designed so that it can be used as a shortcut for busy clinicians, researchers, or patients to find the likely best evidence.
  3. Designed to assist clinicians to conduct their own rapid appraisal.

The 2011 OCEMB Levels of Evidence:

  1. Is NOT dismissive of systematic reviews.
  2. Is NOT intended to provide you with a definitive judgment about the quality of evidence.
  3. Will NOT provide you with a recommendation.
  4. Will NOT tell you whether you are asking the right question.

For more information, see Resources — Centre for Evidence-Based Medicine (CEBM), University of Oxford.