Table 2.
Main psychometric characteristics between the parent and child version of the JAMAR
| Parent (N = 22/22) | Child (N = 20/22) | |
|---|---|---|
| Missing values (1st–3rd quartiles) | No missing values | No missing values |
| Response pattern | PF and HRQoL positively skewed | PF and HRQoL positively skewed |
| Floor effect, median | ||
| PF | 86.4% | 85.0% |
| HRQoL PhH | 77.3% | 60.0% |
| HRQoL PsH | 63.6% | 45.0% |
| Pain VAS | 36.4% | 20.0% |
| Disease activity VAS | 50.0% | 25.0% |
| Well-being VAS | 36.4% | 30.0% |
| Ceiling effect, median | ||
| PF | 0.0% | 0.0% |
| HRQoL-PhH | 0.0% | 0.0% |
| HRQoL-PsH | 0.0% | 5.0% |
| Pain VAS | 0.0% | 0.0% |
| Disease activity VAS | 0.0% | 0.0% |
| Well-being VAS | 0.0% | 0.0% |
| Items with equivalent item–scale correlation | 100% for PF, 80% for HRQoL | 87% for PF, 80% for HRQoL |
| Items with item–scale correlation ≥ 0.4 | 100% for PF, 80% for HRQoL | 53% for PF,90% for HRQoL |
| Cronbach’s alpha | ||
| PF-LL | 0.88 | 0.87 |
| PF-HW | 0.85 | 0.53 |
| PF-US | 0.90 | 0.48 |
| HRQoL-PhH | 0.51 | 0.81 |
| HRQoL-PsH | 0.77 | 0.63 |
| Items with item–scale correlation lower than the Cronbach’s alpha | 100% for PF, 80% for HRQoL | 93% for PF, 100% for HRQoL |
| Spearman’s correlation with JIA core set variables, median | ||
| PF | 0.4 | 0.2 |
| HRQoL PhH | 0.4 | 0.2 |
| HRQoL PsH | 0.2 | 0.1 |
| Pain VAS | 0.3 | 0.3 |
| Disease activity VAS | − 0.1 | -0.1 |
| Well-being VAS | 0.3 | 0.3 |
JAMAR Juvenile Arthritis Multidimensional Assessment Report, JIA juvenile idiopathic arthritis, VAS Visual Analogue Scale, PF physical function, HRQoL health-related quality of life, PhH physical health, PsH psychosocial health, PF-LL PF-lower limbs, PF-HW PF-hand and wrist, PF-US PF-upper segment