Evidence-based nursing (or evidence-based medicine, or evidence-based practice) is "the practice of nursing in which the nurse makes clinical decisions on the basis of the best available current research evidence, the nurse's clinical expertise, and the needs and preferences of the patient."
From Mosby's Dictionary of Medicine, Nursing, & Health Professions, 2012.
Evidence-based practice includes five steps:
Step 1. Converting the need for information into an answerable question
Step 2. Finding the best evidence with which to answer that question
Step 3. Critically appraising the evidence for its validity, impact, and applicability
Step 4. Integrating the evidence with clinical expertise and the patient's unique biology, values, and circumstances
Step 5. Evaluating the effectiveness and efficiency of the process
Strauss, S.E. (2005). Evidence-based medicine: How to practice and teach EBM (3rd ed.). New York: Elsevier/Churchill Livingstone.