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. 2006 Jan 1;6(2):1–67.
Grade of recommendation Clarity of risk/benefit Strength of Supporting Evidence Implications
1A Benefits clearly outweigh risk and burdens, or vice versa Consistent evidence from well performed randomized, controlled trials or overwhelming evidence of some other form. Further research is unlikely to change our confidence in the estimate of benefit and risk. Strong recommendation, can apply to most patients in most circumstances without reservation
1B Benefits clearly outweigh risk and burdens, or vice versa Evidence from randomized, controlled trials with important limitations (inconsistent results, methodological flaws, indirect or imprecise), or very strong evidence of some other form. Further research (if performed) is likely to have an impact on our confidence in the estimate of benefit and risk and may change the estimate. Strong recommendation, likely to apply to most patients
1C Benefits appear to outweigh risk and burdens, or vice versa Evidence from observational studies, unsystematic clinical experience, or from randomized, controlled trials with serious flaws. Any estimate of effect is uncertain. Relatively strong recommendation; might change when higher quality evidence becomes available.
2A Benefits closely balanced with risks and burdens Consistent evidence from well performed randomized, controlled trials or overwhelming evidence of some other form. Further research is unlikely to change our confidence in the estimate of benefit and risk. Weak recommendation, best action may differ depending on circumstances or patients’ or societal values
2B Benefits closely balanced with risks and burdens; some uncertainty in the estimates of benefits, risks, and burdens Evidence from randomized, controlled trials with important limitations (inconsistent results, methodological flaws, indirect or imprecise), or very strong evidence of some other form. Further research (if performed) is likely to have an impact on our confidence in the estimate of benefit and risk and may change the estimate. Weak recommendation, alternative approaches likely to be better for some patients under some circumstances.
2C Uncertainty in the estimates of benefits, risks, and burdens; benefits may be closely balanced with risks and burdens Evidence from observation studies, unsystematic clinical experience, or from randomized, controlled trials with serious flaws. Any estimate of effect is uncertain. Very weak recommendation; other alternatives may be equally reasonable.