Table 1.

The grading of recommendations, assessment, development, and evaluation (GRADE) system

Criteria
Quality of evidence
High quality	Further research is very unlikely to change our confidence in the estimate of the effect.	A
Moderate quality	Further research is likely to have an important impact on our confidence in the estimate of the effect and may change the estimate.	B
Low quality	Further research is very likely to have an important impact on our confidence in the estimate of the effect and is likely to change the estimate. Any change of estimate is uncertain.	C
Strength of recommendation
Strong	Factors influencing the strength of the recommendation include the quality of the evidence, presumed patient-important outcomes, and cost.	1
Weak	Variability in preference and values or greater uncertainty. The recommendation is made with less certainty, higher cost or resource consumption.	2