| MEASUREMENT PROPERTIES | |
| Limitations | >=5 European languages (English) |
| Observations | |
| 1. RELIABILITY | |
| A. Internal Consistency | Tested |
| Cronbach's (Describe) |
Cronbach's α of 0.92 has been reported |
| 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 | 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) |
The RADAI and RADAI‐5 items score the most apparent symptoms of RA with the exception of joint scores. No physician‐derived measures of disease activity or laboratory parameters are included in either measurement tool. |
| B. Construct Validity: Structural validity |
Tested |
| Hypotheses-testing | Tested |
| Cross-cultural validity | Not Tested |
| Brief Description |
Factor analysis by principal component analysis reveals both the RADAI and RADAI‐5 to be 1‐dimensional instruments with all items contributing significantly to the final scores |
| C. Criterion validity | Tested |
| Comparison with a 'gold standard' Continuous scores: correlations, ROC curves Dichotomus: Sensitivity & Specificity (Describe) |
The RADAI‐5 is significantly correlated (P < 0.001) with TJCs (0.60) and SJCs (0.60); however, it was not correlated significantly with erythrocyte sedimentation rate or C‐reactive protein (CRP) level |