VALIDATION DATA

The recall period within JAMAR differs according to the specific measure. The measures within the JAMAR ask respondents to consider their symptoms and experiences in the moment, today, in the past week, in the past 4 weeks, and since their last doctor visit.

Internal consistency for the US English version of JAMAR was adequate. Specifically, Cronbach's α was 0.88 for PF-LL, 0.87 for PF-HW, and 0.72 for PF-US. Cronbach's α was 0.86 for HRQoL-PH and 0.77 for HRQoL-PsH.

 In the English version, test-retest reliability assessed a median of 3 days after initial measure was excellent (ICC = 0.92). Additionally, the ICC for the HRQoL-PhH and for the HRQoL-PsH was almost perfect (ICC = 0.92 and ICC = 0.83, respectively).

With regard to agreement between parent proxy and child self-reported data in paired questionnaires, findings are mixed. Filocamo et al found that responses for parent-child pairs were similar for most items other than one question about medication side effects, in which parents more often reported hypertrichosis as a side effect. Vanoni et al found an increased number of items with disagreement between parents and children when the disease was more active.

Filocamo et al examined whether the child's age affected the reliability of completion of the questionnaire. Results across the three age groups (less than 10, 10-15, and more than 15 years) were comparable, with the exceptions of a lower correlation of functional ability assessment in the younger age group and of psychosocial HRQoL assessment in the older age group

Face validity was established first by content review of medical personnel, including 12 physicians (eight pediatric rheumatologists and four pediatric residents), four physical therapists, three specialist nurses, and one clinical psychologist. Additionally, a sample of 49 children with JIA and their parents completed the draft questionnaire and provided comments about the design, content, structure, and response scale

With regard to the US English version of the JAMAR, the JAMAR components discriminated well between healthy subjects and patients with JIA. Patients with JIA had a greater level of disability and pain as well as a lower HRQoL than their healthy peers