Table 1 Evidence classification criteria.
Evidence class | Description |
|---|---|
Class I: convincing evidence | > 1000 cases (or> 20000 participants for continuous outcomes); statistical significance at P < 10−6 (random effects); no evidence of small-study effects and excess significance bias; 95% prediction interval excluded null value; no large heterogeneity (I2 < 50%) |
Class II: highly suggestive evidence | > 1000 cases (or> 20000 participants for continuous outcomes), statistical significance at P < 10−6 (random effects), and largest study with 95% confidence interval excluding null value |
Class III: suggestive evidence | > 1000 cases (or> 20000 participants for continuous outcomes) and statistical significance at P < 0.001 |
Class IV: weak evidence | Remaining significant associations with P < 0.05 |
NS: non-significant | P> 0.05 |
