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Step 2. Identify Appropriate Sources of Evidence

Once you have a question, you'll need to decide where to start your search. Your question topic and the type of evidence required will guide your selection. To find the best evidence, you need to know about the breadth of sources that are available to you, the relative quality of these sources, and how to match questions to a source to search.


In this section, you'll:
  • Recognize that evidence varies in quality (e.g. merit, relevance, validity)
  • Understand that different types of literature are acquired from a range of sources
  • Identify sources of evidence that are appropriate to your question topic

Recognizing the quality of evidence

Before you start searching, it is important to understand that the quality of evidence between sources and studies can vary greatly.


The Hierarchy of Evidence in EBM

In practicing evidence-based medicine, you want to choose research that represents the highest level of evidence. The pyramid below demonstrates the EBM hierarchy and corresponds to increasing rigour, quality, and reliability of the evidence for different types of study designs. We can become more confident that a study's results are accurate as we move up the pyramid.

To learn more, click on the individual icons or plus signs in the pyramid.

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What if there is no high-level evidence sources or filtered literature on your topic?

Filtered articles may not always be available. In this case, you will need to search for primary or unfiltered evidence. Just remember to be vigilant of the validity and reliability of the studies you find.