Levels of Evidence

The levels of evidence are assigned to studies in relation to methodological quality of their design, validity, and applicability of patient care. The levels of evidence range from level I, level II, level III, Level IV, and level V.

1. Level I evidence is regarded as a highly quality evidence and it is acquired from high quality randomized trial and prospective studies, testing of previously diagnostic criteria, data from multiway sensitivity analysis and systematic reviews of level I studies
2. Level II; this is evidence acquired from less quality randomized controlled trials (RCT), values acquired from limited studies, systematic review of level II studies or Level I study that have inconsistent results.
3. Level III: this include case control studies such as therapeutic and prognostic studies. May also include study of nonconsecutive patients with no consistently applied reference of gold standards.
4. Level IV; involved case series, case studies from diagnostic studies, studies with poor reference standard, and analysis with no sensitivity analysis
5. Level V; this evidence is comprised of expert opinion.

Use in Evidence-Practice

The classification of the evidence is done to ensure that researchers deal with cognitive errors that are bound to occur due to inferences made through various human observation methods. A key principle in evidence-based practice is based on the recognition of the fact the not all evidence is error proof. Evidence based practice refers to the clinical decision-making that depends on sound external research evidence combined with individua clinical expertise and needs of the individual patient. The goal of the evidence-based practice is to improve patient’s outcomes, quality of care and therefore achieve some standardization of treatment. This indicates the need of having quality evidence to inform the evidence-based practice. In this case it is important to establish the relevance and weight of evidence (Burns et al, 2011).

Reference

Burns, P. B., Rohrich, R. J., & Chung, K. C. (2011). The Levels of Evidence and their role in Evidence-Based Medicine. Plastic and Reconstructive Surgery, 128(1), 305–310.

Wright, J. G., Swiontkowski, M. F., & Heckman, J. D. (2003). Introducing levels of evidence to the journal. Journal of Bone and Joint Surgery, 85(1), 1.