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Table 5 Scale-level psychometrics

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

Scale Reliability
α r ii Mean* SD* Pearsonrwith IADCQ*
IADCQ 0.927 0.52 21.62 10.77 **
SF-12 v2: PF 0.801 0.67 47.32 11.33 −0.32
SF-12 v2: RP 0.884 0.79 44.05 10.22 −0.42
SF-12 v2: BP (1 item) ** 45.32 11.26 −0.40
SF-12 v2: GH (1 item) ** 46.38 11.31 −0.20
SF-12 v2: VT (1 item) ** 45.84 10.41 −0.33
SF-12 v2: SF (1 item) ** 42.23 11.11 −0.54
SF-12 v2: RE 0.860 0.76 39.14 11.47 −0.48
SF-12 v2: MH 0.690 0.43 41.96 10.40 −0.57
SF-12 v2: PCS 0.875 0.56 48.18 10.43 −0.26
SF-12 v2: MCS 0.817 0.43 40.17 10.14 −0.58
  1. Abbreviations: α, coefficient alpha; BP, bodily pain; GH, general health; IADCQ, Impact of Alzheimer’s Disease on Caregiver Questionnaire; MCS, mental health composite score; MH, mental health; PCS, physical health composite score; PF, physical functioning; r ii , average inter-item correlation; RE, role emotional; RP, role physical; SD, standard deviation; SF, social functioning; SF-12v2, Short Form-12 Health Survey Version 2; VT, vitality.
  2. *T-scores for SF-12v2 scales were used in calculation.
  3. **Analyses were not conducted.