"The process of systematically finding, appraising and using the best available research findings, integrated with clinical expertise, as the basis for clinical decisions about individual patients. The aim is to encourage clinicians, health-service managers and consumers of health care to make decisions, taking account of the best available evidence, on the likely consequences of alternative decisions and actions." (from Black's Medical Dictionary, 43rd Edition)
Various pyramid models have been used to depict the hierarchial value of data in the research process. What is similar in all models is the role of Systematic Reviews and Meta-Analysis as the pinnacle for evidence based practice.
Where Evidence-Based Medicine comes together.