Table 2Definitions for grading the strength of evidence

GradeDefinition
HighThere is high confidence that the evidence reflects the true effect. Further research is very unlikely to change our confidence in the estimate of effect.
ModerateModerate confidence that the evidence reflects the true effect. Further research may change our confidence in the estimate of effect and may change the estimate.
LowLow confidence that the evidence reflects the true effect. Further research is likely to change our confidence in the estimate of effect and is likely to change the estimate.
InsufficientEvidence either is unavailable or does not permit estimation of an effect.

From: Methods

Cover of Venous Thromboembolism Prophylaxis in Orthopedic Surgery
Venous Thromboembolism Prophylaxis in Orthopedic Surgery [Internet].
Comparative Effectiveness Reviews, No. 49.
Sobieraj DM, Coleman CI, Tongbram V, et al.

PubMed Health. A service of the National Library of Medicine, National Institutes of Health.