Grading of evidence
| Grade of recommendation . | Definition . | Level of evidence . |
|---|---|---|
| A | Requires ≥1 RCT as part of a body of literature of overall good quality and consistency addressing specific recommendation | Evidence levels Ia, Ib |
| B | Requires the availability of well-conducted clinical studies but no randomized clinical trials on the topic of recommendation | Evidence levels IIa, IIb, III |
| C | Requires evidence obtained from expert committee reports or opinions and/or clinical experiences of respected authorities. Indicates an absence of directly applicable clinical studies of good quality. | Evidence level IV |
| Grade of recommendation . | Definition . | Level of evidence . |
|---|---|---|
| A | Requires ≥1 RCT as part of a body of literature of overall good quality and consistency addressing specific recommendation | Evidence levels Ia, Ib |
| B | Requires the availability of well-conducted clinical studies but no randomized clinical trials on the topic of recommendation | Evidence levels IIa, IIb, III |
| C | Requires evidence obtained from expert committee reports or opinions and/or clinical experiences of respected authorities. Indicates an absence of directly applicable clinical studies of good quality. | Evidence level IV |
Adapted from the National Guidelines Clearinghouse (www.guideline.gov).