| MEASUREMENT PROPERTIES | |
| Limitations | >=5 European languages (English) |
| Observations | |
| 1. RELIABILITY | |
| A. Internal Consistency | Tested |
| Cronbach's (Describe) |
The original scale has moderate internal consistency (Cronbach’s a 0.71–0.80 for long version and 0.56–0.83 for short version). These moderate reliabilities were obtained despite the small number of items on each of the scales and the inventory’s true-false format (which limits the range of responding). |
| B. Reliability intraobserver or test-retest | Tested |
| Continuous scores: intraclass correlation coefficient (ICC) Dichotomus: Cohen kappa (Describe) |
Except for the disability subscale, the r values fell between 0.7 and 0.9 (high correlation). For the paired t test, all subscales (except for control and medication) had a P value greater than 0.05, confirming their test-retest stability. |
| 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 | Not Tested |
| Expert opinion (relevance and comprehensiveness) (Describe) |
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| B. Construct Validity: Structural validity |
Tested |
| Hypotheses-testing | Tested |
| Cross-cultural validity | Tested |
| Brief Description |
The factor structure of the SOPA was examined using a principal components analysis with varimax rotation. While 12 eigenvalues were greater than 1.0, the first 6 factors alone accounted for 48.27% of the total variance. |
| C. Criterion validity | Not Tested |
| Comparison with a 'gold standard' Continuous scores: correlations, ROC curves Dichotomus: Sensitivity & Specificity (Describe) |
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