Table 3.

GRADE Approach

1. Establish the initial level of certainty		2. Consider lowering or raising the level of certainty		3. Final level of certainty rating
Study design	Initial confidence in an estimate of effect	Lower if	Higher if	Certainty in an estimate of effect across those considerations
Randomized controlled trials	High	Risk of bias	Large effect	⊕⊕⊕⊕ High
Observational studies	Low	Inconsistency	Dose response	⊕⊕⊕Ο Moderate
		Indirectness	All plausible confounding and bias would reduce a demonstrated effect or would suggest a spurious effect if no effect was observed	⊕⊕ΟΟ Low
		Imprecision		⊕ΟΟΟ Very low
		Publication bias

GRADE = Grading of Recommendation Assessment, Development, and Evaluation.