Table 2 Overview of the GRADE system for grading the quality of evidence (Adapted from Reference[7]): A) Criteria for assigning grade of evidence; B) Definitions in grading the quality of evidence.
From: The need to reform our assessment of evidence from clinical trials: A commentary
A) | Â |
|---|---|
Criteria for assigning level of evidence | |
Type of Evidence | Â |
   Randomized trial | High |
   Observational study | Low |
   Any other type of research evidence | Very low |
Increase level if: | Â |
   Strong association | (+1) |
   Very strong association | (+2) |
   Evidence of a dose response gradient | (+1) |
   Plausible confounders reduced the observed effect | (+1) |
Decrease level if: | Â |
   Serious or very serious limitations to study quality | (-1) or (-2) |
   Important inconsistency | (-1) |
   Some or major uncertainty about directness | (-1) or (-2) |
   Imprecise or sparse data* | (-1) |
   High probability of reporting bias | (-1) |
B) | Â |
Definitions for levels of evidence | |
High | Further research is not likely to change our confidence in the effect estimate |
Moderate | Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate |
Low | Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate |
Very Low | Any estimate of effect is uncertain |