Table 1

Grades of quality of evidence in GRADE [24]

High = We are very confident that the true effect lies close to that of the estimate of the effect.


Moderate = We are moderately confident in the effect estimate: The true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different.


Low = Our confidence in the effect estimate is limited: The true effect may be substantially different from the estimate of the effect.


Very low = We have very little confidence in the effect estimate: The true effect is likely to be substantially different from the estimate of effect.


Fretheim et al. BMC Medicine 2012 10:33   doi:10.1186/1741-7015-10-33

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