C-DVT 應用於思覺失調患者之再測信度分析結果簡述

再測信度
C-DVT綜合4次評估之再測一致性 (test-retest agreement)達良好之程度 (ICC=0.80，Table 1)；隨機測量誤差小 (SEM%=4.9~9.2，Table 2)；練習效應於第3次評估後即消失 (Cohen’s d=-0.14，Table 2及Figure 1)。
DVT之再測一致性優於C-DVT (ICC=0.93，Table 1)；然而DVT之隨機測量誤差偏大 (SEM%=7.1~10.9，Table 2)，且第3次評估後仍具小的練習效應 (Cohen’s d=0.25，Table 2)。

Table 1. Mean, SD, and ICC of the C-DVT and DVT (n=45)

Tests	Time 1	Time 2	Time 3	Time 4	ICC (95% CI)
	Mean ± SD	Mean ± SD	Mean ± SD	Mean ± SD
C-DVT	290.9 ± 49.5	281.4 ± 39.6	275.7 ± 41.2	278.5 ± 43.3	0.80 (0.70, 0.87)
DVT	558.0 ± 227.0	546.8 ± 232.1	527.0 ± 187.7	514.1 ± 185.3	0.93 (0.88, 0.96)

Table 2. Parameters of random measurement error and practice effect of the C-DVT and DVT (n=45)

Tests	Adjacent assessments	ICC (95% CI)	SEM* (SEM%)	MDC	SDdiff	Cohen’s d†
C-DVT (seconds)	Time 1-2	0.72 (0.53, 0.83)	26.2 (9.2)	72.6	33.2	0.28
	Time 2-3	0.88 (0.79, 0.94)	13.7 (4.9)	38.0	18.9	0.31
	Time 3-4	0.87 (0.78, 0.93)	14.9 (5.4)	41.3	21.2	-0.14
DVT (seconds)	Time 1-2	0.93 (0.88, 0.96)	60.1 (10.9)	166.6	85.6	0.13
	Time 2-3	0.94 (0.90, 0.97)	56.9 (10.6)	157.7	68.8	0.29
	Time 3-4	0.96 (0.93, 0.98)	37.5 (7.1)	103.9	51.5	0.25

此外C-DVT具可接受之同時效度 及生態效度。

同時效度：C-DVT與DVT之Pearson's r=0.41~0.65 (Figure 2)；

生態效度：C-DVT與Lawton IADL scale之Pearson's r=-0.32~-0.44；DVT與Lawton IADL scale之Pearson's r=-0.33~-0.41。

Figure 1. Practice effects of the C-DVT and DVT

Figure 2. Correlation between the C-DVT and DVT