| MEASUREMENT PROPERTIES | |
| Limitations | >=5 European languages (English) |
| Observations | |
| 1. RELIABILITY | |
| A. Internal Consistency | Tested |
| Cronbach's (Describe) |
In OA: Cronbach’s alpha: 0.90–0.98. Cronbach’s alphas for the Likert scale 0.90–0.94, and for the VAS 0.94–0.98. In RA: Cronbach's alpha for total score: 0.90 |
| B. Reliability intraobserver or test-retest | Tested |
| Continuous scores: intraclass correlation coefficient (ICC) Dichotomus: Cohen kappa (Describe) |
In OA: ICCs ranged from 0.70–86 for the Likert scale and from 0.94–0.98 for the VAS. In RA: ICCs ranged from 0.92–0.93 for the subscales and 0.94 for the total scales |
| C. Reliability interobserver or Measurement error | Not Tested |
| Standard error of measurement (SEM), smallest detectable change (SDC) or Limits of agreement (LoA) (Describe) |
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| 2. VALIDITY | |
| A. Content validity: face validity | Tested |
| Expert opinion (relevance and comprehensiveness) (Describe) |
Patient centered development of the items. Items were generated from interactions between experts (health providers) and interviews with patients. Items were retained that had a prevalence of >60% in the sample population and a mean importance rating >2.0 (scale from 1–5). Patients were involved in development of the questionnaire. The development of the subscales is not described well. Item response theory was not used in development or item selection. |
| B. Construct Validity: Structural validity |
Tested |
| Hypotheses-testing | Tested |
| Cross-cultural validity | Tested |
| Brief Description |
Factor analysis supported the pain and function subscales. |
| C. Criterion validity | Not Tested |
| Comparison with a 'gold standard' Continuous scores: correlations, ROC curves Dichotomus: Sensitivity & Specificity (Describe) |
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