Skip to Main Content

NURS303/307 - Nursing Seminar/Nursing Trends: EBP

Books & eBooks

Levels of Evidence

Evidence Pyramid

Wagoner, B. et al. (2004) 'Guide to Research Methods: The Evidence Pyramid', in SUNY Downstate Medical Center: EBM Tutorial,
formerly available at:

The Evidence Pyramid is an easy way to visualize levels of evidence for types of research articles. At the base is animal research and expert opinion. These are still important, but are low in the evidence-based hierarchy.

The next step up, from case reports to randomized control trials, is unfiltered evidence. These are individual reports and studies, also known as the primary literature

At the top of the pyramid, representing the strongest evidence, is filtered evidence. Systematic reviews and meta-analyses are literature reviews that analyze multiple research studies. Clinical Practice Guidelines can be added to this list of secondary literature

When doing evidence-based research, seek the highest level of evidence available. Just remember that the top levels may not be available for your particular clinical question. In that case, seek the next level down!

What is Evidence-Based Practice?

Evidence based practice (EBP) is the conscientious use of current best evidence in making decisions about patient care (Sackett, Straus, Richardson, Rosenberg, & Haynes, 2000).

Types of Research Studies

What is a case study? What is a cohort study? And what about a randomized controlled trial? 

Evidence-Based Nursing Concepts