Grading the evidence: Levels of evidence and grades of recommendation

Evidence-based medicine is using the best available evidence in order to make accurate and knowledgeable treatment decisions. It is not the automatic gainsay of low quality evidence and acceptance of randomized controlled trials (RCT's). To be able to make a sound recommendation for a therapy based on the best available evidence, it is necessary to follow steps in acquiring literature, appraising it for study design and quality, and to assess its results, as well as took at the net benefits and net harms. (C) 2006 Published by Elsevier Ltd.