TABLE 2.
Tests of heterogeneity between and within the moderator subgroups.
| Moderator | QB (df) | p | QW (df) | p | I2 |
| Research design | 29.06 (1) | <0.0001 | 5639.74 (955) | <0.0001 | 83.4% |
| Publication type | 6.15 (1) | <0.05 | 5699.39 (957) | <0.0001 | 83.4% |
| Outcome measure | 14.12 (3) | <0.001 | 4380.69 (750) | <0.0001 | 83.0% |
| Feedback type | 41.52 (2) | <0.0001 | 1541.06 (316) | <0.0001 | 80.9% |
| Feedback channel | 5.12 (2) | >0.05 | 2218.20 (337) | <0.0001 | 85.2% |
| Feedback direction | 9.35 (2) | <0.001 | 4695.60 (852) | <0.0001 | 81.9% |
QB, heterogeneity between groups; QW, heterogeneity within groups; I2, total amount of heterogeneity.