Table 1 Factors that may lead to downgrading or upgrading of evidence in the GRADE approach
Criteria for downgrading | By how many levels |
|---|---|
1. Serious risk of bias | Serious (- 1) or very serious (- 2) limitation to study quality |
2. Serious inconsistence between studies | Important inconsistency, lack of agreement between studies or conflicting results (- 1) |
3. Serious indirectness | Uncertainty with generalisability of population or outcomes (- 1) or with both population and outcomes (- 2) |
4. Serious imprecision | Imprecise or sparse data (- 1) |
5. Likely publication bias | High probability of reporting bias (- 1) |