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Nursing Resources

Welcome! This guide provides an effective way to locate library information and essential resources specifically related to nursing students, staff and faculty.

Step 3: Appraise

In this step you critically appraise the evidence for its validity, impact, and usefulness in clinical practice. If you do not use a systematic reviews database, you will have to appraise whether or not the research is clinically sound. There are many different types of research studies, including prognosis, diagnosis, harm/etiology, and therapy.

Suggested Readings:

Hierarchy of Evidence

Adapted from: Melnyk, B. M. & Fineout-Overholt, E. (2005). Evidence-Based Practice in
Nursing & Healthcare: A Guide to Best Practice, Philadelphia, PA: Lippincott Williams & Wilkins.

Systematic Reviews and Meta-Analysis
Randomized Control Trials
Control Studies
Case Controlled or Cohort Studies                     
Qualitative Studies
Single descriptive or qualitative study
Expert committee opinions

Clinical Question/Best Level of Evidence

Type of Clinical Question

Suggested Level of Evidence


RCT > cohort > case control > case series


Prospective, blind comparison to a gold standard


RCT > cohort  > case control > case series


Cohort study > case control > case series


RCT > cohort study > case control > case series

Clinical Exam

Prospective, blind comparison to gold standard


economic analysis

Questions of therapy, etiology, and prevention, which can best be answered by a RCT, can also be answered by a meta-analysis or systematic review.

The hierarchy of evidence is often presented as a pyramid, ranking study types based on their research methods, with systematic reviews and meta-analyses at the top, and expert opinion and anecdotal experience at the bottom.