While definitions vary depending upon the area of application, all refer to the use of scientific research as a way to inform delivery of patient care. The Cochrane Collaboration states:
"Evidence-based health care is the conscientious use of current best evidence in making decisions about the care of individual patients or the delivery of health services. Current best evidence is up-to-date information from relevant, valid research about the effects of different forms of health care, the potential for harm from exposure to particular agents, the accuracy of diagnostic tests, and the predictive power of prognostic factor."
"A process involving creating an answerable question based on a client or organizational need, locating the best available evidence to answer the question, evaluating the quality of the evidence as well as its applicability, applying the evidence, and evaluating the effectiveness and efficiency of the solution." (NASW, Evidence Based Practice)
The National Association of Social Workers (NASW) defines a broader process that encompasses the AOA's goals for evidence-based optometry. They define evidence-based practice as:
The AOA Evidence-based Optometry Committee has undertaken the challenge of developing clinical practice guidelines and providing resources that will markedly improve health care quality by ensuring patients are diagnosed and treated based on the best available scientific research.
 Cochrane AL. Effectiveness and Efficiency : Random Reflections on Health Services. London: Nuffield Provincial Hospitals Trust, 1972. Reprinted in 1989 in association with the BMJ. Reprinted in 1999 for Nuffield Trust by the Royal Society of Medicine Press, London, ISBN 1-85315-394-X. (temporarily out of print; new edition scheduled for early 2013)