| MEASUREMENT PROPERTIES | |
| Limitations | >=5 European languages (English) |
| Observations | |
| 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) |
In RA: ICCs= 0.89-0.97 In OA: ICCs= 0.94-0.96 In SSc: ICC= 0.97 The Bland and Altman method showed no systematic trend. |
| 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) |
Content or face validity was determined by collecting a list of hand activity questions from published indices. The questions were divided into 5 categories and given to 10 subjects. These subjects added other items and evaluated items for clarity. It was then administered to 102 subjects. Questions that were “never done” by <5% of subjects were eliminated, yielding 18 items. Patients were involved in development of items. Items were grouped by content to generate subscales. Item-response theory was not used in development or item selection. |
| B. Construct Validity: Structural validity |
Tested |
| Hypotheses-testing | Tested |
| Cross-cultural validity | Tested |
| Brief Description |
Factor analysis extracted four factors with eigenvalues>1, which accounted for 65% of the total variance. The first factor represents activities requiring grip strength, the second, activities requiring dexterity and precision, the third, activities requiring pinch strength and the fourth, activities requiring pinch dexterity of the dominant hand. |
| C. Criterion validity | Tested |
| Comparison with a 'gold standard' Continuous scores: correlations, ROC curves Dichotomus: Sensitivity & Specificity (Describe) |
As there is no gold standard to assess functional disability, only construct validity was assessed. |