| MEASUREMENT PROPERTIES | |
| Limitations | |
| Observations | |
| 1. RELIABILITY | |
| A. Internal Consistency | Tested |
| Cronbach's (Describe) |
Moderate internal consistency: Cronbach's alpha of 0.71–0.85 |
| B. Reliability intraobserver or test-retest | Tested |
| Continuous scores: intraclass correlation coefficient (ICC) Dichotomus: Cohen kappa (Describe) |
Good test-retest reliability: estimated kappa of 0.78 to detect low compliance. |
| 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) |
In the development of the CQR, thirty-two patients participated in semistandardized home interviews about their attitude toward their antirheumatic medication, actual drug intake, and reasons for not taking medication and a focus group interview with 7 patients (3 RA, 2 PMR, 2 gout) was held. |
| B. Construct Validity: Structural validity |
Not Tested |
| Hypotheses-testing | Not Tested |
| Cross-cultural validity | Not Tested |
| Brief Description | |
| C. Criterion validity | Not Tested |
| Comparison with a 'gold standard' Continuous scores: correlations, ROC curves Dichotomus: Sensitivity & Specificity (Describe) |
A discriminant analysis was performed to test the predictive value of the CQR. The classification table of the calculated discriminant function of the CQR versus MEMS data to detect taking compliance ≤ 80% shows a sensitivity and specificity of 62% (95% confidence interval 56.8, 67.3%) and 95% (95% CI 92.2, 97.1%), respectively. The likelihood ratio for a positive test result (e.g., to detect taking compliance ≤ 80%) was 11.6 (95% CI 6.7, 20.1). Sensitivity and specificity to detect unsatisfactory correct dosing (≤ 80%) was 89% (95% CI 85.0, 91.9%) and 70% (95% CI 64.7, 74.7%), respectively. The corresponding likelihood ratio to detect correct dosing ≤ 80% is therefore 2.9 (95% CI 1.5, 5.9). |