General

The purpose of evidence-based practice (EBP) is to use the best available evidence to make informed patient-care decisions that ultimately improve the treatment outcomes and safety of treatment for patients. How pharmacologic agents affect patients is often the subject of research; such research is required by the Food and Drug Administration (FDA) before and after drug approval. Any medication can be the subject of an evidence-based clinical review. But what does "evidence-based" mean, and how does it relate to nursing?

Evidence-based nursing practice can be viewed as a foundation of professional practice. It is an approach to making decisions, providing nursing care, and improving clinical practice based upon clinical expertise in combination with the most current and relevant research evidence. Still subject to debate are questions about the sufficiency and quality of evidence. For example, what kind of evidence is needed? How much evidence is necessary to support, modify, or change clinical practice? And were the studies reviewed of "good" quality and are their results valid?

Clinicians use a hierarchy of evidence to rank types of research reports from the most valuable and scientifically rigorous to the least useful. The hierarchy makes clear that some level of evidence about the effect of a particular treatment or condition exists, even if the evidence is considered weak. Figure 1 illustrates a hierarchy of evidence pyramid with widely accepted rankings: the most scientifically rigorous at the top, the least scientifically rigorous at the bottom. Clinicians should look for the highest level of available evidence to answer their clinical questions. It is important that clinicians also apply the second fundamental principle of EBP, which is that evidence alone is not sufficient to make clinical decisions. Decision makers must always trade off the benefits and risks, as well as the costs associated with alternative treatment options, and consider the patient's values and preferences.

Figure 1: Hierarchy of Scientific Evidence Pyramid