Evidence-Based Practice in Nursing & Healthcare

Even though all evidence may be useful for medical practice, different types of evidence vary in their value for evidence-based practice (EBP). There are different levels of evidence, depending on its quality and methods. Melnyk and Fineout-Overholt (2019) provide a review of the strength-of-evidence rating pyramid that helps to visualize these levels. According to this pyramid, the strongest evidence is received from summaries, such as systematic reviews or meta-analyses of randomized control trials (RCT). Experimental research studies, such as RCTs, form the second level of evidence, while the non-experimental studies are rated third. The weakest evidence is received from qualitative studies, expert opinions, theory, and basic science. Therefore, it may be stated that top-quality evidence can be acquired from secondary literature. However, the existence of systematic reviews, meta-analyses, practice guidelines, and critically appraised topics (CATs) is impossible without primary literature, which is qualitative and quantitative research.

While there are different levels of evidence, all of them matter regardless of the method that is used, as long as it adheres to ethical standards. EBP is born in the synthesis of research results, patient preferences, and clinical expertise. Any type of evidence is valuable for the synthesis to be performed since it can be critically appraised and integrated into further research or clinical practice. Additionally, different types of clinical questions are best answered by different types of research studies. For instance, prevention is best addressed through RCTs, while prognoses are usually done using cohort studies (“Levels of evidence,” n.d.). Therefore, all the levels of evidence are essential for research and practice disregarding the method used.