Fig. 2.

Bland–Altman plots: agreement between children with mobility impairments and parent proxies for EQ-5D-Y a, VAS b, HUI2 c and HUI3 d. On the plots 95% of differences should lie between the established limits of agreement (mean difference ± 1.96 SD), represented as dashed lines. Where bias or limits of agreement are beyond those deemed acceptable for clinical use, the measures lack agreement to be used interchangeably to measure the same construct. The EQ-5D-Y and HUI measures are scored on a 0 to 1 scale, while the VAS is scored on a 0 to 100. For the purpose of this comparison, the VAS has been converted to a 0 to 1 scale