What levels of evidence are present in relation to research and practice?

In evidence-based practice, levels of evidence are assigned to studies depending on the methodological quality of the design, validity, and applicability to clinical practice. As outlined by Melnyk and Fineout-Overholt (2015) the rating system for the levels of evidence start from level I to level VII. In particular, Level I encompasses evidence from systematic reviews or meta-analysis from all relevant random controlled trials. Level II is evidence obtained from well-designed random controlled trials. Level II includes evidence from well-designed non-random controlled trials. Level IV involves evidence from well-designed cohort and case-control studies. Level V includes evidence obtained from systematic reviews of qualitative and descriptive studies. Level VI encompasses evidence from qualitative or a single-descriptive study. Lastly, level VII includes evidence from expert committees and authorities’ opinions.

Why it is important regardless of the method you use?

Notably, evidence-based practice is about finding evidence and applying it to make informed clinical decisions. According to Eyal and Igor (2016), not all evidence is created equal and classifying available evidence using the hierarchical system of classification helps to grade available literature based on the strength of evidence. As a practical application of levels of evidence, for instance, randomized controlled trials are considered high levels of evidence as compared to case reports. The goals of applying evidence-based practice is to choose the most appropriate intervention that is likely to deliver results that consider the best interests of the patient and prevent potential harmful results. In light of this, the strength of the evidence is important despite the method used, alongside the clinical applicability, validity, and relevance of the evidence. Thus, along with using levels of evidence as the basis to assess evidence, it is important to consider significance and applicability.

References

Eyal, R., & Igor, T. (2016). Classifying scientific evidence as the basis for evidence-based decision making: is strength of evidence absolute?. Evidence-based Endodontics, 1(1), 1-5.Melnyk, B. M., & Fineout-Overholt, E. (2015). Evidence-based practice in nursing & healthcare: A guide to best practice. Philadelphia: Wolters Kluwer.