Table 4.

Absolute Test Statistics With Significance for Difference of Bivariate Correlation Coefficients Between Dependence Measures and Outcomes of Interest for Concurrent Validity

	Vape per month	Vape per weekend day	Vape per weekday	Nicotine concentration
PS-ECDI vs. EDS	2.681**	13.570***	14.108***	0.307
PS-ECDI vs. self-perceived	0.296	12.824***	13.138***	1.369
PS-ECDI vs. time from waking	3.624***	14.117***	14.291***	1.795
EDS vs. self-perceived	2.379*	0.682	0.903	1.681
EDS vs. time from waking	0.942	0.528	0.163	2.110*
Self-perceived vs. time from waking	3.320***	1.208	1.067	0.420

EDS = E-Cigarette Dependence Scale; PS-ECDI = Penn State Electronic Cigarette Dependence Index.

*p < .05.

^**  p < .01.

^***  p < .001.