Dugoua et al listed levels of evidence for therapeutic efficacy of an herbal remedy.
Evidence of Benefit Based on |
Strength |
Grade |
statistically significant evidence of benefit in one or more systematic reviews |
very strong scientific |
A |
statistically significant evidence of benefit in one or more properly conducted random control trials (RCT) |
strong scientific |
B1 |
statistically significant evidence of benefit in one or more random control trials (RCT) with methodologic problems (small size, discrepancies, etc) |
good scientific |
B2 |
cohort or case control studies |
weak scientific |
C |
case reports or case series |
very weak scientific |
D |
expert opinion or in vitro experiments |
indirect |
E |
based on traditional or historical use, including word of mouth |
historical or traditional |
F |
where:
• Something that is statistically significant may not be significant in practice.
• Performance of a systematic review presumes multiple properly conducted random control trials.
ICD-10: ,