- Evidence Based Practice GuideDesigned to familiarize health science students with concepts and strategies used in EBP. Includes levels of evidence, question formulation (PICO), and information sources for evidence.
Identifying nursing research
Levels of Evidence
How strong is the evidence found in your study? The following 'evidence pyramid' shows the strongest evidence (at the top) and the weakest evidence (at the bottom). In your paper you may discuss the relative strength of the evidence found in your different studies.
Adapted from Stillwell, Fineout-Overhold, Melynk, & Williamson (2010).
Qualitative Research
This evidence pyramid shows the relative evidence strength for different types of qualitative research.
Best Types of Studies for Clinical Queries
What is the best type of study for your question? Use this guide:
Levels of evidence
Where can you find the different types of studies? This is a list of appropriate databases where you can search for studies.
Level 1: Systematic Reviews & Meta-analysis of RCTs; Evidence-based Clinical Practice Guidelines
Search: Cochrane Database of Systematic Reviews | PubMed | Medline | CINAHL | Nursing Reference Center
Level 2: One or more Randomized Control Trials (RCTs)
Search: PubMed | Medline | CINAHL
Level 3: Controlled Trials (no randomization)
Search: PubMed | Medline | CINAHL
Level 4: Case-control or Cohort study
Search: PubMed | Medline | CINAHL
Level 5: Systematic Review of Descriptive and Qualitative studies
Search: PubMed | Medline | CINAHL
Level 6: Single Descriptive or Qualitative Study
Search: PubMed | Medline | CINAHL
Level 7: Expert Opinion
Search: Nursing Reference Center | PubMed | Medline | CINAHL