Table 1 Power to determine the number of studies needed to show a moderator effect in a given meta-analysis dataset
From: Risk of bias: a simulation study of power to detect study-level moderator effects in meta-analysis
|  | Proportion of studies (%) with positive expression of moderator (for example, ‘high quality’) | |||
|---|---|---|---|---|
Studies ( n ) | 0.5 | 0.3 | 0.2 | 0.1 |
Moderator effect = 0 | ||||
200 | 6 | 6 | 5 | 6 |
400 | 6 | 5 | 6 | 5 |
600 | 5 | 6 | 6 | 6 |
800 | 6 | 5 | 6 | 7 |
Moderator effect = 0.1 | ||||
200 | 24 | 22 | 22 | 13 |
400 | 45 | 40 | 33 | 21 |
600 | 65 | 54 | 48 | 29 |
800 | 75 | 69 | 53 | 39 |
Moderator effect = 0.2 | ||||
200 | 75 | 67 | 57 | 32 |
400 | 95 | 93 | 84 | 60 |
600 | 100 | 99 | 96 | 78 |
800 | 100 | 100 | 98 | 90 |