| MEASUREMENT PROPERTIES | |
| Limitations | >=5 European languages (English) |
| Observations | |
| 1. RELIABILITY | |
| A. Internal Consistency | Tested |
| Cronbach's (Describe) |
It has shown high internal consistency (Cronbach's alphas ranging from 0.86 to 0.93 for the various factors) |
| B. Reliability intraobserver or test-retest | Tested |
| Continuous scores: intraclass correlation coefficient (ICC) Dichotomus: Cohen kappa (Describe) |
Excellent test-retest reliability was found (ICC of 0.97) |
| 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 |
Regarding structural validity, the NPDS is a multidimensional scale, with moderate evidence that the NPDS has a three-factor structure (with explained variance ranging from 63 to 78%): neck dysfunction related to general activities; neck pain and neck-specific function; and cognitive-emotional-behavioural functioning After the physical therapy and rehabilitation program, significant correlations were detected between the patient satisfaction scores and NPDS score (r = − 0.634, p < 0.001,). Significant correlations were found between the changes in VAS-pain scores after the treatment and the changes in NPDS (r = 0.659, p < 0.001). Additionally, significant correlations were determined between the changes in VAS-disability scores and the changes in NPDS scores (r = 0.759, p < 0.001) |
| C. Criterion validity | Not Tested |
| Comparison with a 'gold standard' Continuous scores: correlations, ROC curves Dichotomus: Sensitivity & Specificity (Describe) |
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