What are Levels of Evidence?
When you start researching you will encounter many different types of evidence such as systematic reviews, randomized controlled trials, clinical guidelines and opinion articles. These different resources will not all have the same "weight" in terms of reliability and trustworthiness. To assist you in determining what is the most reliable, the levels of evidence hierarchies will guide you.
Evidence Hierarchies are systems used to rank evidence according to certain criteria. There are many hierarchies, including the examples on this page.
Source:
Hopp, L., & Rittenmeyer, L. (2012). Introduction to evidence-based practice: A practical guide for nursing. Philadelphia: F.A. Davis.
Levels of Evidence Tutorial
- UIC Evidence-Based Practice in the Health Sciences: Evidence-Based Nursing TutorialTutorial describing the levels of evidence. The Research Design section provides helpful definitions and information.
These resources provide additional information on the levels of evidence.
Best Types of Evidence for Question - Melnyk
Source:
Melnyk, B.M. & Fineout-Overholt, E. (2010). Evidence-based practice in nursing & healthcare: A guide to best practice (2nd edition). Philadelphia, PA: Wolters Kluwer/Lippincott Williams & Wilkins.
JBI Levels of Evidence
The Joanna Briggs Institute adopted a new hierarchy for levels of evidence as of March 1, 2014. The chart below outlines the levels of evidence for effectiveness questions.
The Joanna Briggs website contains levels of evidence charts for other types of questions.
Levels of Evidence Pyramid
This evidence pyramid provides a concept of higher to lower levels of evidence.
Source: UIC Evidence Based Practice Tutorial, ebp.lib.uic.edu
