Scoring and psychometric validation of the Perception of Anticoagulant Treatment Questionnaire (PACT-Q©)

Table 4 Psychometric validation of the PACT-Q2 dimensions for the 3 population subsets

Population subsets	Cronbach's alpha	Floor effect^c (%)	Ceiling effect^d (%)	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	0.33–0.64^a
Anticoagulant Treatment Satisfaction	0.76	0.4	3.3	0.33–0.63^b

^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.

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