Table 3.

Motives predicting likelihood of simultaneous alcohol and marijuana (SAM) use on alcohol days and on marijuana days

Predictor	Estimate (SE)	t	p
Multilevel model for alcohol days
Level 2 (between person)
Male sex	0.06 (0.20)	0.29	.771
Attending 4-year college (vs. not)	0.02 (0.20)	0.08	.939
Coping (person mean)	1.01 (0.21)	4.85***	<.001
Social (person mean)	-0.94 (0.17)	-5.67***	<.001
Enhancement (person mean)	0.81 (0.16)	5.12***	<.001
Conformity (person mean)	-0.48 (0.20)	-2.47*	<.05
Level 1 (within person)
Day in study (0 to 13)	-0.03 (0.02)	-1.78	.076
Weekend (vs. not)	0.31 (0.13)	2.37*	<.05
Coping (person centered)	0.38 (0.14)	2.73**	<.01
Social (person centered)	0.08 (0.08)	0.96	.338
Enhancement (person centered)	0.65 (0.10)	6.66***	<.001
Conformity (person centered)	0.24 (0.11)	2.17*	<.05
Multilevel model for marijuana days
Level 2 (between person)
Male sex	-0.27 (0.20)	-1.36	.176
Attending 4-year college (vs. not)	-0.54 (0.20)	-2.69**	<.01
Coping (person mean)	0.13 (0.20)	0.62	.534
Social (person mean)	0.36 (0.17)	2.12*	<.05
Enhancement (person mean)	0.07 (0.15)	0.47	.638
Conformity (person mean)	-0.27 (0.20)	-1.34	.180
Level 1 (within person)
Day in study (0 to 13)	0.01 (0.02)	0.80	.422
Weekend (vs. not)	0.62 (0.12)	5.03***	<.001
Coping (person centered)	-0.07 (0.14)	-0.53	.597
Social (person centered)	1.08 (0.09)	11.95***	<.001
Enhancement (person centered)	0.25 (0.10)	2.50*	<.05
Conformity (person centered)	0.31 (0.12)	2.62**	<.01

Notes: The model predicting any SAM use on alcohol days included 1,917 days nested in 381 participants. The model predicting any SAM use on marijuana days included 2,166 days nested in 326 participants. Current education status was coded as 1 (attending a 4-year college or university) and 0 (all other options). Weekend refers to the day on which the behavior occurred (i.e., alcohol or marijuana use) and was coded 1 (Thursday, Friday, Saturday) and 0 (all other days).

^*p < .05;

^**p < .01;

^***p < .001.