| MEASUREMENT PROPERTIES | |
| Limitations | <5 European languages (English) |
| Observations |
The original CSI is validated in more then 5 European Languages |
| 1. RELIABILITY | |
| A. Internal Consistency | Tested |
| Cronbach's (Describe) |
Cronbach's alpha of CSI-25 and CSI-9 were 0.89 and 0.80, respectively. McDonald's Omega of CSI-25 and CSI-9 were also 0.89 and 0.80, respectively. These results suggest that both versions of CSI have good internal consistency. |
| B. Reliability intraobserver or test-retest | Tested |
| Continuous scores: intraclass correlation coefficient (ICC) Dichotomus: Cohen kappa (Describe) |
Of the participants who reported no change (the difference between first and second round of pain intensity during movement is under 10 mm) in pain intensity during the past 2 weeks (n = 100), in CSI-25 and CSI-9, there was excellent agreement between test and retest total scores, with an ICC of 0.86 (95% confidence interval [CI], 0.80± 0.9) and 0.79 (95% CI, 0.71±0.85), respectively. |
| C. Reliability interobserver or Measurement error | Tested |
| Standard error of measurement (SEM), smallest detectable change (SDC) or Limits of agreement (LoA) (Describe) |
Standard Error of Measurement ranges 0.05-0.07 for the 9 included items |
| 2. VALIDITY | |
| A. Content validity: face validity | Tested |
| Expert opinion (relevance and comprehensiveness) (Describe) |
The face validity of the CSI-9 items is very good. For instance, the items correspond very well with the current criteria for fibromyalgia, using the Widespread Pain Index and Symptom Severity Score, which assesses widespread pain distribution, fatigue, unrefreshed sleep, and cognitive symptoms. CSI-9 adequately comprises all five components of CSS (emotional distress = item 15, urological and general symptom = items 9 and 23, muscle symptom = items 2 and 18, headache/jaw symptoms = item 10, sleep disturbance = items 1 and 12, and not loading = item 13). |
| B. Construct Validity: Structural validity |
Tested |
| Hypotheses-testing | Tested |
| Cross-cultural validity | Not Tested |
| Brief Description |
Principal Component analysis (PCA) of the residuals indicated that the unexplained variance of the first contrast of CSI-25 and CSI-9 was 2.2 and 1.6 eigenvalue units, respectively, indicating multidimensionality of CSI-25 and unidimensionality of CSI-9. A two-factor model in the CSI-9 was the most fitted to the data |
| C. Criterion validity | Not Tested |
| Comparison with a 'gold standard' Continuous scores: correlations, ROC curves Dichotomus: Sensitivity & Specificity (Describe) |
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