Nursing

Guide for library resources in the Nursing field

Levels of Evidence

Melnyk Model:
I. Systematic reviews or meta-analyses of RCTs
II. Well-designed RCTs
III. Well-designed, controlled trials without randomization
IV. Well-designed cohort and case-control studies
V. Systematic reviews of descriptive and qualitative studies
VI. Descriptive and qualitative studies
VII. Expert consensus reports

Melnyk model pyramid of evidence showing seven levels labeled I to VII from top to bottom.

Source: Melnyk, B.M. & Fineout-Overholt, E. (2011). Evidence-based practice in nursing and healthcare: A guide to best practice. Philadelphia: Lippincott, Williams & Wilkins.

Example PICO Questions

Example PICO Statements from CINAHL Evidence based practice care sheets:

1. In the elderly at risk of falling, is tai chi effective in reducing the risk and preventing falls as compared with those who do not practice tai chi?

2. Are alcohol based hand rubs more effective or less effective in reducing HRI's than soap and water techniques?

3. Is peer-pressure more effective than educational interventions in improving hand hygiene practices?

4. Are PPI's (proton pump inhibitors) effective medical therapy for esophagitis and GERD in children and adolescents?

5. In older adults with wandering, is music therapy or exercise/activities more effective in decreasing wandering/pacing?