Impact of Alzheimer’s Disease on Caregiver Questionnaire: internal consistency, convergent validity, and test-retest reliability of a new measure for assessing caregiver burden

Table 4 Item-level psychometrics

IADCQ item	Concept	Correlation with total	Cronbach’s coefficient alpha
Item 1	Physical health	0.672	0.921
Item 2	Impact on time	0.780	0.917
Item 3	Sadness	0.637	0.922
Item 4	Loneliness	0.701	0.920
Item 5*	Worry	0.523	0.928
Item 6	Frustration	0.729	0.919
Item 7	Social activities	0.723	0.919
Item 8	Relationship with AD patient	0.637	0.923
Item 9	Relationship with friends or family	0.763	0.918
Item 10	Personal finances	0.579	0.925
Item 11	Sleep	0.763	0.917
Item 12	Stress	0.785	0.917
Overall coefficient alpha			0.927

Abbreviation: AD, Alzheimer’s disease.
*The correlation of Item 5 is significantly different from the average correlation of the entire scale, where z score is 2.7 and p value is 0.006.

ISSN: 1477-7525