Table 4.
Population subsets | Cronbach's alpha | Floor effectc (%) | Ceiling effectd (%) |
Convergent and discriminant validity criterion (range of item-scale correlations) |
"scoring and initial validation" (n = 452) | ||||
Convenience | 0.83 | 0 | 21.2 | 0.31–0.63 |
Anticoagulant Treatment Satisfaction | 0.79 | 0.6 | 4.0 | 0.36–0.66 |
"robustness" (n = 200) | ||||
Convenience | 0.87 | 0 | 24.1 | 0.40–0.67 |
Anticoagulant Treatment Satisfaction | 0.70 | 0 | 1.9 | 0.26–0.59 |
"pooled" (n = 652) | ||||
Convenience | 0.84 | 0 | 22.1 | 0.33–0.64a |
Anticoagulant Treatment Satisfaction | 0.76 | 0.4 | 3.3 | 0.33–0.63b |
a except items B10 and B11, all items meet the convergent validity criterion
b except items D2 and D3, all items meet the convergent validity criterion
c percentage of patients with the lowest possible score (i.e. 0), that is patients who answered the least favourable response choice to all items of the dimension.
d percentage of patients with the highest possible score (i.e. 100), that is patients who answered the most favourable response choice to all items of the dimension.