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Systematic Reviews

Information on how to conduct systematic reviews in psychology and the health sciences

Levels of Evidence

Levels of evidence are a way to designate the strength of studies based on the methodological quality of their design, validity, and applicability to patient care. The lowest level is at the bottom of the pyramid, the highest is on the top. It is important to use the highest level of evidence that you can for a systematic review, recognizing that for some topics, you may need to use lower quality studies.

SR levels of evidence pyramid

Guides to Other Levels of Evidence

National Health and Medical Research Council has created a guide to help researchers perform their search. How to Use the Evidence: Assessment and Application of Scientific Evidence

The Joanna Briggs Institute offers a guide to their Levels of Evidence based on the research design of the original experiment.

Centre for Evidence Based Medicine (UK) uses another system for rating evidence used in a systematic review- Levels of Evidence (March 2009)