Table 2.
Multiple meta-regression analysis, predicting between-study variance in unidimensional outcomes using the level of similarity between active and sham control groups for a number of selected features in spinal manipulation trials.
| Descriptives | |||||||
|---|---|---|---|---|---|---|---|
| Mean ES | Mean (SD) similarity rating (n of sessions) | Mean (SD) similarity rating (efficacy information) | Mean (SD) similarity rating (environment) | R 2 | k | ||
| −0.33 | 1.91 (0.37) | 0.6 (1.03) | 1.43 (0.74) | 0.5934 | 35 | ||
| Homogeneity analysis | |||||||
|---|---|---|---|---|---|---|---|
| Q | df | P | T 2 | I2 | |||
| Model | 50.33 | 3 | 0.0000 | 0.077 | 94.0% | ||
| Residual | 34.49 | 31 | 0.30 | 0.006 | 10.1% | ||
| Total | 82.15 | 34 | 0.0000 | ||||
| Regression coefficients | |||||||
|---|---|---|---|---|---|---|---|
| B | SE | −95% CI | +95% CI | Z | P | Beta | |
| Constant | −2.64 | 0.36 | −3.35 | −1.93 | −7.27 | 0.0000 | 0.0000 |
| Similarity: N of sessions | 1.09 | 0.19 | . 72 | 1.47 | 5.75 | 0.0000 | . 65 |
| Similarity: efficacy information | 0.13 | 0.05 | 0.02 | 0.23 | 2.3 | 0.02 | 0.27 |
| Similarity: environment | 0.07 | 0.08 | −0.08 | 0.22 | 0.89 | 0.37 | 0.11 |
| Method of moments random effects variance component | |||||||
| v = 0.03 | |||||||
Means and variance of the similarity ratings included in the model are provided, having a possible range of −2 (different for all studies) to 2 (similar across all studies).