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Nursing 360: Intro to EBP & Evidence Pyramid

Resources and tutorials for NURS 360

What is evidence-based practice?

Evidence-based practice (EBP) is "a problem-solving approach to practice that involves the conscientious use of current best evidence in making decisions about patient care."  It involves a systematic search for the most relevant evidence, as well as critical appraisal of the quality (or level) of this evidence to answer a clinical question. 

Sources:  Bennet, C. (2007).  Evidence-based practice

Evidence-Based Practice, Step by Step

This series of 12 articles, provided free from the AJN: American Journal of Nursing website, begins with the development of the clinical (PICO) question and carries the reader through the appraisal of evidence, implementation, and dissemination of best practices. 


Levels of Evidence Hierarchy

Several types of research articles are commonly found in the literature for medical and health sciences, and each type can be assigned to a level within the hierarchy of levels described below. Systematic reviews, meta-analyses, randomized clinical trials and controlled trials, are considered to be stronger forms of evidence than levels 4-7.  

Evidence Pyramid

  • Level I:  Systematic review - assessment of evidence by some systematic method, where all the components of the approach and the assessment are made explicit and documented.  Some systematic reviews include meta-analysis. 
    Meta-analysis - A statistical analysis of data from multiple randomized controlled trials (RCTs), in order to help determine the effectiveness of a given health care intervention.
    Evidence-based clinical practice guidelines - based on systematic reviews
  • Level II:  Randomized controlled trial - Experimental study in which users are randomly allocated to one of two or more options, where some get the option of interest and others get another option (e.g. a standard intervention or no intervention)
  • Level III:  Clinical trial or Controlled trial without randomization (quasi-experimental)
  • Level IV:  Single nonexperimental study (case-control, correlational, cross-sectional, longitudinal, or cohort studies)
  • Level V:  Systematic review of descriptive or qualitative studies 
  • Level VI:  Single descriptive or qualitative studies
  • Level VII: Opinion of authorities/experts, Reports of expert committees, Quality improvement reports, Evidence-based practice projects ‚Äč

Search Tips:

To find levels I,II, and III evidence in CINAHL, limit your search by Publication Type.   In PubMed, limit your search by Article Type.

CINAHL Publication Types, Levels 1-3

Clinical Trial
Evidence-Based Care Sheet
Meta Analysis
Nursing Interventions
Practice Guidelines
Randomized Controlled Trial
Systematic Review

To find Level IV evidence in CINAHL, clear any other limiters you have used, you may copy/paste this search string into one of the search boxes in your CINAHL search screen:  
case-control OR correlational OR cross-sectional OR longitudinal OR cohort




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Mary Kraljic

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