Bland-Altman and ICC agreement between child-parent pairs on VQoL_CYP and FVQ_CYP summary scores
| Child summary score—mean (SD) | Parent summary score—mean (SD) | Mean paired score difference (SD) (95% CI) | Minimum difference | Maximum difference | Bland-Altman lower limit of agreement (CI 95%) | Bland-Altman upper limit of agreement (CI 95%) | ICC (95% CI) | |
|---|---|---|---|---|---|---|---|---|
| VQoL_CYP* | 70.5 (15.1) | 64.8 (15.7) | 5.7 (SD 13.9)† (2.8 to 8.6) | −41 | 37 | −22.10 (−24.61 to −19.59) | 33.50 (30.99 to 36.01) | 0.56 - moderate agreement (0.37 to 0.7) |
| FVQ_CYP* | 49.4 (21.7) | 61.2 (16.8) | −11.8 (SD 13.9)† (−14.8 to −8.9) | −62.9 | 16.8 | −39.60 (−42.12 to −37.08) | 16 (13.48 to 18.52) | 0.63 - good agreement (0.16 to 0.82) |
*On VQoL_CYP, higher scores indicate better vision-related quality of life outcome, whereas on the FVQ_CYP higher scores indicate greater functional vision difficulty.
†Paired t test difference significant at p<0.001. FVQ_CYP functional vision questionnaire for children and young people; ICC, Intraclass Correlation Coefficient; VQoL_CYP, vision-related quality of life instrument for children and young people.