. 2017 Apr 4;9:26. doi: 10.1186/s13195-017-0251-0

Table 2.

Correlation of perseverance time with related measures for assessment of construct validity and responsiveness

	Construct validity^a			Responsiveness^b
	Study A	Study B	Pooled data	Study A
CSI	−0.45^c	−0.40^c	−0.42^c	0.27^d
SRB	−0.62^c	−0.36^c	−0.50^c	0.28^d
CarerQol-7D	0.32^c	0.46^c	0.39^c	N/A
CarerQol-VAS	0.23^c	0.28^c	0.25^c	−0.23^d
Objective burden	−0.24^c	−0.28^c	−0.26^c	0.10
IC VAS health	0.19^c	0.15	0.17^c	−0.19
PwD VAS health	0.10	−0.01	0.05	N/A

Abbreviations: CarerQol Care-related Quality of Life instrument, VAS Visual analogue scale, IC Informal caregiver, PwD People with dementia, SRB Self-rated Burden scale, CSI Caregiver Strain Index, N/A Not applicable, because these measures were not included in the follow-up measurement

^a Correlations between actual scores

^b Correlations between change scores over time. Change in perseverance time was used as a positive or negative difference in number of ordered answering categories between follow-up and baseline. Change in other scores is used as continuous difference between follow-up and baseline

^c p < 0.05

^d p < 0.01