Levels of Evidence
Select an evidence rating scale to display detailed information.
Key to interpretation of practice guidelines
Agency for Healthcare Research and Quality:
A: | There is good research-based evidence to support the recommendation. |
B: | There is fair research-based evidence to support the recommendation. |
C: | The recommendation is based on expert opinion and panel consensus. |
X: | There is evidence of harm from this intervention. |
USPSTF Guide to Clinical Preventive Services:
A: | There is good evidence to support the recommendation that the condition be specifically considered in a periodic health examination. |
B: | There is fair evidence to support the recommendation that the condition be specifically considered in a periodic health examination. |
C: | There is insufficient evidence to recommend for or against the inclusion of the condition in a periodic health examination, but recommendations may be made on other grounds. |
D: | There is fair evidence to support the recommendation that the condition be excluded from consideration in a periodic health examination. |
E: | There is good evidence to support the recommendation that the condition be excluded from consideration in a periodic health examination. |
University of Michigan Practice Guideline:
A: | Randomized controlled trials. |
B: | Controlled trials, no randomization. |
C: | Observational trials. |
D: | Opinion of the expert panel. |
Other guidelines:
A: | There is good research-based evidence to support the recommendation. |
B: | There is fair research-based evidence to support the recommendation. |
C: | The recommendation is based on expert opinion and panel consensus. |
X: | There is evidence that the intervention is harmful. |