Table 3.

Internal consistency and test−retest reliability.

	OT	OD	OI	TDI
Test-retest reliability (n = 22)
Mean concordance correlation a	0.45	0.44	0.66	0.56
Intraclass correlation	0.49 *	0.48 *	0.69 **	0.6 **
Pearson’s correlation	0.51 *	0.48 *	0.69 **	0.6 **
Internal consistency (n = 209)
Cronbach’s alpha	0.95	0.46	0.53	0.4
Spearman−Brown coefficient	0.95	0.43	0.46	0.4

* p < 0.05, ** p < 0.01. ^a No inferential test is performed. CI = Confidence interval.