Why is the hierarchy of evidence not necessarily applicable to nursing research studies?

The hierarchy of evidence is not necessarily applicable to nursing research because it only ranks research designs by how useful they are for determining the effectiveness of clinical interventions or treatments, which is not the full scope of nursing decisions and practices. Nursing research draws on diverse disciplines and addresses humanistic, context-dependent questions where the hierarchy may not fit.

The Cochrane collaboration developed the hierarchy of evidence as part of the evidence-based practice movement, which originated in medicine and focused on demonstrating the efficacy and effectiveness of treatments and medicines. The hierarchy only relates to how useful different research designs are for determining whether clinical interventions or treatments work. In that context, it is noted as not necessarily applicable to the design and findings of nursing research studies. Nursing is theoretically pluralistic, informed by medical sciences, social sciences, technology, and other disciplines, and nursing research addresses a wide range of practices and decisions. There is also ongoing debate about whether the philosophy and principles of evidence-based practice are relevant to the essence of nursing or to the types of decisions nurses make, including what counts as appropriate evidence, how different sources of knowledge are legitimized, and how to justify decisions when no relevant evidence exists.