Evidence-based practice is a conscientious, problem-solving approach to clinical practice that incorporates the best evidence from well-designed studies, patient values and preferences, and a clinician’s expertise in making decisions about a patient’s care. Unfortunately, no standard formula exists for how much these factors should be weighed in the clinical decision-making process. However, there are a variety of rating systems and hierarchies of evidence that grade the strength or quality of evidence generated from a research study or report. Being knowledgeable about EBP and levels of evidence is important to every clinician because clinicians need to be confident about how much emphasis they should place on a study, report, practice alert or clinical practice guideline when making decisions about a patient’s care.
The levels of evidence listed here have been developed with the help of nurse experts and other industry resources. We thank those who have contributed to making our system relevant and applicable to determining the levels of evidence that support our CE publications.
Evidence-based information ranges from Level A (the strongest) to Level C (the weakest). In 2013, we have added Level ML, multilevel, to identify clinical practice guidelines that contain recommendations based on more than one level of evidence:
LEVEL A: Evidence obtained from:
LEVEL B: Evidence obtained from:
LEVEL C: Evidence obtained from:
LEVEL ML (multilevel): clinical practice guidelines, recommendations based on evidence obtained from:
More than one level of evidence as defined in our rating system.
Evidence-based Practice Resources:
References for EBP
Alfaro-LeFevre R. Critical Thinking, Clinical Reasoning, and Clinical Judgment: A Practical Approach. 5th ed. Philadelphia, PA: Elsevier-Saunders; In Press, 2013.
Ebell MH, Siwek J, Weiss BD, et al. Strength of recommendation taxonomy (SORT): a patient centered approach to grading evidence in the medical literature. Am Fam Physician. 2004;69(3):548-556. http://www.aafp.org/afp/2004/0201/p548.html. Published February 1, 2004. Accessed June 6, 2014.
Evidence-based medicine toolkit. American Academy of Family Physician Website.
http://www.aafp.org/online/en/home/publications/journals/afp/ebmtoolkit.html. Accessed June 6, 2014.
What is evidence based medicine? University of Illinois at Chicago University Library Web site. Updated April 17, 2014. Accessed June 6, 2014.
Levels of evidence. Centre for Evidence-Based Medicine Website. http://www.cebm.net/index.aspx?o=1025. Published March 2009. Updated September 16, 2013. Accessed June 6, 2014.
Melnyk BM, Fineout-Overholt E. Evidence-Based Practice in Nursing & Healthcare. A Guide to Best Practice. Philadelphia, PA: Lippincott Williams & Wilkins. 2005.
Newhouse RP, Dearholt SL, Poe SS, Pugh LC, White KM. Johns Hopkins Nursing Evidence-Based Practice Model and Guidelines. Indianapolis, IN: Sigma Theta Tau International; 2007.
Strength of Recommendation Taxonomy (SORT). American Academy of Family Physicians Website.
http://www.aafp.org/online/en/home/publications/journals/afp/afpsort.html. Published February 1, 2004. Accessed June 6, 2014.
Understanding research study designs. University of Minnesota Biomedical Library Website. Accessed June 6, 2014.