| MEASUREMENT PROPERTIES | |
| Limitations | >=5 European languages (English) |
| Observations | |
| 1. RELIABILITY | |
| A. Internal Consistency | Tested |
| Cronbach's (Describe) |
Cronbach’s alpha was calculated before and after surgery and varied between 0.84–0.93 (3, 6, 12, and 24 months) |
| B. Reliability intraobserver or test-retest | Tested |
| Continuous scores: intraclass correlation coefficient (ICC) Dichotomus: Cohen kappa (Describe) |
In the test-retest sample, the differences between the first and second scores were plotted against their means. The scatter appeared normal and showed the same variability across the range of scores at all levels of disability/severity. The estimated mean (–0.73) of score differences was not significantly different from 0. The coefficient of reliability was calculated as 7.27 using Bland and Altman’s method and 95% of score differences fell between 0 ± 7.27. Overall, 81% of score differences lay between 0 ± 4. |
| C. Reliability interobserver or Measurement error | Tested |
| Standard error of measurement (SEM), smallest detectable change (SDC) or Limits of agreement (LoA) (Describe) |
Minimal important change in cohort studies is aprox 11 points and in individual patients aprox 8 points. Smallest detectable change is 5 points. (Beard, 2015) |
| 2. VALIDITY | |
| A. Content validity: face validity | Tested |
| Expert opinion (relevance and comprehensiveness) (Describe) |
Questions were based on patient interviews where hip OA patients were asked to report their experience and problems. Patients were involved in face and content validity of the questionnaire |
| B. Construct Validity: Structural validity |
Tested |
| Hypotheses-testing | Tested |
| Cross-cultural validity | Tested |
| Brief Description |
OHS underwent item-response theory testing in (Fitzpatrick, 2004) and there was an overall good item fit of the data to the Rasch model. |
| C. Criterion validity | Not Tested |
| Comparison with a 'gold standard' Continuous scores: correlations, ROC curves Dichotomus: Sensitivity & Specificity (Describe) |
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