NUR 49800: Capstone Course in Nursing: 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.

The Pyramid of Evidence:

What's Not in the Pyramid of Evidence?

There are some types of sources you may encounter that aren't on the pyramid of evidence. These sources may be useful for your understanding, but should not be cited as scientific evidence. Examples of these include: Blogs, magazine or new articles, and popular non-academic sites such as Wikipedia.

• These types of sources do not reflect primary research, nor are they an expert review of primary research the way clinical practice guidelines or systematic reviews are.
• They may refer to or summarize research articles. Locate the research article rather than cite a journalist's summary of it. Wikipedia will include linked citations to the original sources. 

Adapted with permission from What is Evidence-Based Practice? by Grand Canyon University Library: https://libguides.gcu.edu/Nursing/ebp

Source:

Melnyk, B.M. & Fineout-Overholt, E. (2010). Evidence-based practice in nursing & healthcare: A guide to best practice (2^nd edition). Philadelphia, PA: Wolters Kluwer/Lippincott Williams & Wilkins.