Table 3 Statistical comparison of the profiles of limitations between studies with positive and negative results
Risk of bias | Imprecision | |||||
|---|---|---|---|---|---|---|
Total number of key questions judged to be at high risk of bias | Number of key questions judged to be at high risk of bias in favour of a null result | Number of key questions judged to be at high risk of bias with uncertain direction on study outcome | Studies with key question judged to be at high risk of bias in favour of an effect of exposure | Studies judged to have concern regarding statistical power | Studies judged to have concern regarding missing adjustment for multiple comparisons when relevant | |
Median (Interquartile range) | Median (Interquartile range) | Median (Interquartile range) | n (%) | n (%) | n (%) | |
Studies with positive results | 3.0 (4.0) | 2.0 (4.0) | 1.0 (2.0) | 2 (29%) | 6 (86%) | 2 (29%) |
Studies with negative results | 2.0 (2.0) | 2.0 (1.5) | 0 (1.5) | 5 (26%) | 15 (71%) | 10 (48%) |
Test statistics and p-values | Mann-Whitney-U: U = 55.5 p = 0.351,4 | Mann-Whitney-U: U = 65.0 p = 0.682,4 | Mann-Whitney-U: U = 54.5 p = 0.322,4 | Fisher’s exact: p = 1.002 | Fisher’s exact: p = 0.643 | Fisher’s exact: p = 0.663 |