Figure 3

Results of an influence analysis in which the meta-analysis is re-estimated omitting each study in turn. Rerunning the analysis without the study by Mathias and Kent [32] increased the standardised mean difference (SMD) from 0.72 to 0.79 (95% CI 0.68 to 0.90). The straight vertical lines at 0.72, 0.53 and 0.91 represent the SMD and upper and lower 95% confidence intervals of the complete study analysis.