Table 2.

Bivariate Correlations Between Standardized Dependence Measures and Indices of Dependence Providing Evidence of Convergent Validity

	PS-ECDI	EDS	Self-perceived addiction	Intention to quit
PS-ECDI	—	—		−0.0335
				n = 1166
EDS	0.7119***	—		−0.0706*
	n = 1164			n = 1180
Self-perceived addiction	0.6749***	0.7187***		−0.0829**
	n = 1143	n = 1156		n = 1161
Time from waking	0.4858***	0.6399***	0.6061***	−0.1076***
	n = 1170	n = 1184	n = 1161	n = 1185

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

*p < .05.

^**  p < .01.

^***  p < .001.