| MEASUREMENT PROPERTIES | |
| Limitations | English only |
| Observations | |
| 1. RELIABILITY | |
| A. Internal Consistency | Tested |
| Cronbach's (Describe) |
Cronbach alpha = 0.86; item response Theory (IRT) person separation reliability = 0.88) |
| B. Reliability intraobserver or test-retest | Tested |
| Continuous scores: intraclass correlation coefficient (ICC) Dichotomus: Cohen kappa (Describe) |
Test–retest reliability was high; ICC was 0.95(95% CI 0.90–0.98) |
| 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) |
In the IRT analysis of the symptom severityscale, item locations, associated standard errors, and fitstatistics suggested that the Partial Credit Model seemed to fit most items |
| B. Construct Validity: Structural validity |
Tested |
| Hypotheses-testing | Not Tested |
| Cross-cultural validity | Not Tested |
| Brief Description |
The 6-item CTS symptoms scale showed strong correlation with the QuickDASH (r = 0.70) and agreement with the original symptom severity scale (ICC = 0.80). The CTS-6 has also shown good agreement with the 11-item Boston symptom severity score. DIF analysis of the symptom severity scale (Table 2)showed statistically significant DIF in item location for item3 (higher for women) and item 7 (higher for men), andanalysis of the functional status scale showed significantdifferences in item location for items 1 and 2 (higher forwomen) and items 5 and 7 (higher for men). |
| C. Criterion validity | Tested |
| Comparison with a 'gold standard' Continuous scores: correlations, ROC curves Dichotomus: Sensitivity & Specificity (Describe) |
There was a statistically significant difference between the CTS-6 scores before and after carpal tunnel injection. |