| MEASUREMENT PROPERTIES | |
| Limitations | >=5 European languages (English) |
| Observations | |
| 1. RELIABILITY | |
| A. Internal Consistency | Tested |
| Cronbach's (Describe) |
Pearson reliability: 0.92. |
| B. Reliability intraobserver or test-retest | Tested |
| Continuous scores: intraclass correlation coefficient (ICC) Dichotomus: Cohen kappa (Describe) |
Test-retest ICC = 0.71 (95% CI: 0.60-0.80). |
| 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) |
Following a literature review, semi-structured interviews were conducted with people with arthritis diseases and their networks (e.g. family, health care providers, etc.) to identify a set of skills and behaviours that people need to manage their health effectively. These interviews were supplemented by consultations with key stakeholders, including patient and professional organisations and research experts. After a pilot project of people with arthritis diseases to assess the psychometric properties of the preliminary scale, the scale was reduced from 48 to 17 items using classical and item response theory. |
| B. Construct Validity: Structural validity |
Tested |
| Hypotheses-testing | Tested |
| Cross-cultural validity | Tested |
| Brief Description |
Confirmatory FA Apart from RMSEA, 1-factor model good fit SB x2 (119) ΒΌ 488.70, NNFI 0.96, CFI 0.96, SRMR 0.08, RMSEA (90% CI) 0.11 (0.10-0.12). Confirmatory FA: two-factor model good fit (df 33, P-value= 0.000) except RMSEA = 0.164 above cutoff. |
| C. Criterion validity | Not Tested |
| Comparison with a 'gold standard' Continuous scores: correlations, ROC curves Dichotomus: Sensitivity & Specificity (Describe) |
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