| MEASUREMENT PROPERTIES | |
| Limitations | >=5 European languages (English) |
| Observations | |
| 1. RELIABILITY | |
| A. Internal Consistency | Tested |
| Cronbach's (Describe) |
>0.9 |
| B. Reliability intraobserver or test-retest | Tested |
| Continuous scores: intraclass correlation coefficient (ICC) Dichotomus: Cohen kappa (Describe) |
ICC>0.9 |
| C. Reliability interobserver or Measurement error | Tested |
| Standard error of measurement (SEM), smallest detectable change (SDC) or Limits of agreement (LoA) (Describe) |
SEM values between 4.8 and 8 MDC between 13 and 19 points |
| 2. VALIDITY | |
| A. Content validity: face validity | Tested |
| Expert opinion (relevance and comprehensiveness) (Describe) |
questionnaire contains various domains of activity that were selected by patients and health care providers. |
| B. Construct Validity: Structural validity |
Tested |
| Hypotheses-testing | Not Tested |
| Cross-cultural validity | Tested |
| Brief Description |
Relatively high degree of interitem correlation (ranging from 0.24-0.87) as well as a very high item total correlation (range 0.56-0.89) |
| C. Criterion validity | Tested |
| Comparison with a 'gold standard' Continuous scores: correlations, ROC curves Dichotomus: Sensitivity & Specificity (Describe) |
QDS, ODI (oswestry disability index), roland morris questionnaire, and NPRS, VAS both, HADS store, short form SF 36 - optimal cutoff value was found to be 5 points, with area under the curve=0.850 (95% confidence interval: 0.786-0.914), sensitivity=78%, and specificity=77%. |