|
Source of body of evidence
|
Initial rating of quality
|
Factors that may decrease the quality
|
Factors that may increase the quality
|
Final quality of a body of evidence *
|
|---|
|
Randomised trials
|
High
|
1. Risk of bias
|
1. Large effect
|
High
|
| | |
2. Inconsistency
|
2. Dose–response
| (⊕⊕⊕⊕ or A) |
| | |
3. Indirectness
|
3. All plausible residual confounding would reduce the demonstrated effect or would suggest a spurious effect if no effect was observed
|
Moderate
|
| | |
4. Imprecision
| (⊕⊕⊕◯ or B) |
|
Observational studies
|
Low
|
5. Publication bias
|
Low
|
| | | | (⊕⊕◯◯ or C) |
| | | |
Very low
|
| | | | | (⊕◯◯◯ or D) |
- *Quality of evidence definitions.
- High: Further research is very unlikely to change confidence in the estimate of effect.
- Moderate: Further research is likely to have an important impact on confidence in the estimate of effect and may change the estimate.
- Low: Further research is very likely to have an important impact on confidence in the estimate of effect and is likely to change the estimate.
- Very low: Any estimate of effect is very uncertain.
