Levels of Evidence

EBP graphic illustration. Best Research Evidence, Clinical Expertise and Patience Values & Preferences

Hierarchy of Evidence

Level I - Evidence from a systematic review or meta-analysis of all relevant randomized controlled trials (RCTs) or three+ RCTs of good quality with similar results.

Level II - Evidence from at least one well-designed RCTs

Level III - Evidence obtained from well-designed controlled trials without randomization (i.e. quasi-experimental).

Level IV - Evidence from well-designed case-control or cohort studies

Level V - Evidence from systematic reviews of descriptive and qualitative studies

Level VI - Evidence from single descriptive or qualitative studies

Level VII - Evidence from the opinion of authorities and/or reports of expert committees

Ackley, B. J., Swan, B. A., Ladwig, G., & Tucker, S. (2008). Evidence-based Nursing Care Guidelines: Medical-surgical Interventions. (p. 7)St. Louis, MO: Mosby Elsevier.

Evidence Based Practice

Measurement Tools

Evidence based Practice in Social Work.

Evidence based is the practical application of the findings of the best available current research. The research assignment generally requires the use of scholarly/peer reviewed resources that are less than 10 years old. Theses resources often contain methods (empirical studies, randomized control trials, clinical trials, results, and discussion.)

  • Create an answerable question related to practice needs
  • Conduct research to find the best evidence available to answer that question
  • Examine the evidence and its usefulness
  • Apply research findings with a social worker’s clinical expertise,  the client's needs and the individual case
  • Evaluate the outcome/the effectiveness and efficiency of the solution.

Types of Resources

Hierarchy of Evidence Resources - Pyramid - at base studies, then syntheses, then synopses, then summaries, and at the top systems

Haynes RB. Of studies, syntheses, synopses, summaries and systems: the “5S" evolution of services for evidence-based health care decisions. ACP J Club. 2006 Nov-Dec;145(3):A8-9. 

Meta-Analysis: systematic review - uses quantitative methods to synthesize & summarize results.

Systematic Review: A summary of the literature with explicit methods to perform a comprehensive literature search & critical appraisal of individual studies.

Randomized Controlled Trial:  randomly allocated participants with experimental or control groups & followed over time

Cohort Study:  patients with a condition followed over time & compared with another group without the condition.

Case Control Study: Patients with a specific outcome & participants without that outcome (controls).

Case Report/Case Series: 1 or more with a particular outcome

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