| MEASUREMENT PROPERTIES | |
| Limitations | >=5 European languages (English) |
| Observations | |
| 1. RELIABILITY | |
| A. Internal Consistency | Tested |
| Cronbach's (Describe) |
These 22-itemOAQoL (final version) demonstrated good fit to the Rasch model (X2[44]=44.559, P=0.533) , with an item fit residual mean of -0.228 (1.022) and a PSI of 0.94992. |
| B. Reliability intraobserver or test-retest | Tested |
| Continuous scores: intraclass correlation coefficient (ICC) Dichotomus: Cohen kappa (Describe) |
There was an excellent significant correlation between the 2 total OAQoL scores from time 1 to time 2 (p=0.93), with no systematic differences between the scores on each occasion (z=-0.06,P=0.995), suggesting excellent test–retest reliability. Kappa values for each item ranged from moderate (K=0.512) to excellent (K=0.926), with most items demonstrating values in the range 0.65–0.85. |
| 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) |
Assessed in two phases. First, semistructured interviews were conducted with 44 OA patients to explore the issues associated with impact of OA and to derive items for a draft OAQoL questionnaire. Later, 17 OA patients were interviewed on the relevance, clarity, and ease of completion of the measure in structured interviews. |
| B. Construct Validity: Structural validity |
Not Tested |
| Hypotheses-testing | Tested |
| Cross-cultural validity | Tested |
| Brief Description | |
| C. Criterion validity | Not Tested |
| Comparison with a 'gold standard' Continuous scores: correlations, ROC curves Dichotomus: Sensitivity & Specificity (Describe) |
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