| MEASUREMENT PROPERTIES | |
| Limitations | |
| Observations | |
| 1. RELIABILITY | |
| A. Internal Consistency | Tested |
| Cronbach's (Describe) |
Cronbach’s α for the PRQL was 0.86 for the total score, 0.84 for the PhH subscale and 0.77 for the PsH subscale. |
| B. Reliability intraobserver or test-retest | Tested |
| Continuous scores: intraclass correlation coefficient (ICC) Dichotomus: Cohen kappa (Describe) |
The ICC for test–retest reliability in 35 parents who completed the PRQL a second time after 24 h was 0.91 for the total score, 0.85 for the PhH subscale and 0.92 for the PsH subscale. |
| C. Reliability interobserver or Measurement error | Not Tested |
| Standard error of measurement (SEM), smallest detectable change (SDC) or Limits of agreement (LoA) (Describe) |
|
| 2. VALIDITY | |
| A. Content validity: face validity | Tested |
| Expert opinion (relevance and comprehensiveness) (Describe) |
The draft questionnaire was shown to eight physicians, four physiotherapists, two specialist nurses who were not part of the PRQL group and one clinical psychologist, and their opinion on the suitability of the instrument was asked. Face and content validity were further tested by asking a convenience sample of 42 children with different pediatric rheumatic diseases and their parents. |
| B. Construct Validity: Structural validity |
Tested |
| Hypotheses-testing | Not Tested |
| Cross-cultural validity | Not Tested |
| Brief Description |
Exploratory factor analysis with orthogonal varimax rotation on parents’ questionnaires led to the unambiguous identification of two separate factors: one factor was related to the PhH domain and incorporated items 1–5; the second factor was related to the PsH domain and incorporated items 6–10. |
| C. Criterion validity | Tested |
| Comparison with a 'gold standard' Continuous scores: correlations, ROC curves Dichotomus: Sensitivity & Specificity (Describe) |
The PhH subscale was correlated at a high level (rs>0.7) with parent’s assessment of both child’s overall well-being and pain intensity and at moderate level (rs = 0.4–0.7) with JAFS score and tender and active joint counts. Correlations of PhH score with swollen and restricted joint counts and acute-phase reactants were poor (rs<0.4). Most correlations for the PsH subscale were in the poor range. The construct validity of the PRQL was overall equivalent to that of the Italian version of the CHQ in a convenience sample of 61 JIA patients who had both questionnaires completed by a parent. |