| MEASUREMENT PROPERTIES | |
| Limitations | <5 European languages (English) |
| Observations |
To evaluate feasibility, the response rate was calculated using a sample of 1961 patients. To assess construct validity, mean levels of disease activity and impact were compared across the five levels of PESS. For its sensitivity to change and reliability the study involved 353 patients with RA, and the PESS was assessed at two visits, six months apart. |
| 1. RELIABILITY | |
| A. Internal Consistency | Not Tested |
| Cronbach's (Describe) | |
| B. Reliability intraobserver or test-retest | Tested |
| Continuous scores: intraclass correlation coefficient (ICC) Dichotomus: Cohen kappa (Describe) |
The PESS was moderately reliable in patients with stable disease activity and impact, as determined by the intraclass correlation coefficient (ICC). The ICC between the two visits was 0.72 (95% CI: 0.52, 0.83). |
| C. Reliability interobserver or Measurement error | Not Tested |
| Standard error of measurement (SEM), smallest detectable change (SDC) or Limits of agreement (LoA) (Describe) |
|
| 2. VALIDITY | |
| A. Content validity: face validity | Tested |
| Expert opinion (relevance and comprehensiveness) (Describe) |
Derived from the Patient Acceptable Symptom State (PASS). |
| B. Construct Validity: Structural validity |
Not Tested |
| Hypotheses-testing | Tested |
| Cross-cultural validity | Not Tested |
| Brief Description | |
| C. Criterion validity | Tested |
| Comparison with a 'gold standard' Continuous scores: correlations, ROC curves Dichotomus: Sensitivity & Specificity (Describe) |
The level of crude agreement between ‘very good’ PESS status and remission was excellent (>0.8, except for DAS28). Kappa levels were in the range of moderate agreement. The crude agreement between ‘>=good’ PESS status and disease activity at the level of remission or LDA, was ‘good’ for all scores of disease activity, with the best crude agreement observed with the ACR/EULAR remission criteria and the worst with DAS28. The highest crude agreement was observed between the ‘very good’ status and remission according to the ACR/EULAR Boolean criteria (86.6%). |