| MEASUREMENT PROPERTIES | |
| Limitations | <5 European languages (English) |
| Observations |
The RPDAI may provide an accurate and objective estimation of disease activity. |
| 1. RELIABILITY | |
| A. Internal Consistency | Not Tested |
| Cronbach's (Describe) | |
| B. Reliability intraobserver or test-retest | Not Tested |
| Continuous scores: intraclass correlation coefficient (ICC) Dichotomus: Cohen kappa (Describe) |
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| C. Reliability interobserver or Measurement error | Tested |
| Standard error of measurement (SEM), smallest detectable change (SDC) or Limits of agreement (LoA) (Describe) |
Inter-rater reliability assessed by the intra-class correlation coefficient for the 1118 PGA ratings was 0.51 (CI95%: 0.41-0.64). |
| 2. VALIDITY | |
| A. Content validity: face validity | Tested |
| Expert opinion (relevance and comprehensiveness) (Describe) |
The content validity of the RPDAI, –i.e. the extent to which it represents all aspects of disease activity in RP–, was ensured by the broad range of clinical symptoms included in the RPDAI, as well as by the addition of a laboratory domain, as agreed upon by experts.The face validity of the RPDAI, i.e. its believed ability to evaluate disease activity in RP, was considered satisfactory by the panel of experts |
| B. Construct Validity: Structural validity |
Tested |
| Hypotheses-testing | Not Tested |
| Cross-cultural validity | Not Tested |
| Brief Description |
Item weighting was performed by 26 experts, who assessed the Physician’s Global Assessment (PGA) of disease activity of 43 test cases on a 0-100 scale. Inter-rater reliability assessed by the intra-class correlation coefficient for these PGA ratings was 0.51 (CI95%: 0.41-0.64). Multivariate analysis revealed that the individual weigh of items ranged from 1 to 24. |
| C. Criterion validity | Not Tested |
| Comparison with a 'gold standard' Continuous scores: correlations, ROC curves Dichotomus: Sensitivity & Specificity (Describe) |
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