Table 4.

Number of positive and negative consequences on simultaneous use days compared with alcohol-only days

Variable	No. of negative consequences		No. of positive consequences
	ERR	[95% CI]	ERR	[95% CI]
Level 1
Intercept	1.82	[1.33, 2.49]**	3.44	[2.91, 4.08]**
Simultaneous use (vs. alcohol only)	1.38	[1.12, 1.70] **	1.32	[1.16, 1.51] **
Simultaneous Use × Drinks	0.90	[0.82, 0.99] *	0.90	[0.86, 0.95] **
Weekend (vs. weekday)	1.15	[1.00, 1.33]*	1.02	[0.92, 1.12]
Study day (1–30)	0.99	[0.98, 1.00]	1.00	[0.99, 1.01]
Total drinks	1.18	[1.07, 1.31]**	1.14	[1.09, 1.19]**
Nicotine use (vs. none)	1.31	[1.00, 1.70]*	1.00	[0.81, 1.24]
Other drug use (vs. none)	1.17	[0.84, 1.63]	1.16	[0.99, 1.38]
Level 2
Age	0.98	[0.92, 1.05]	0.92	[0.87, 0.98]**
Male (vs. female)	0.71	[0.49, 1.04]	1.06	[0.83, 1.35]
Mean simultaneous use days	1.03	[0.59, 1.78]	1.23	[0.90, 1.71]
Average drinks	1.16	[1.05, 1.28]**	0.97	[0.91, 1.03]

Notes: No. = number; ERR = event rate ratio; CI = confidence interval. Bold indicates the effects of interest when significant. Day type is coded 1 = simultaneous use, 0 = alcohol-only use; sex is coded 0 = female, 1 = male; weekend is coded 0 = Sunday–Thursday, 1 = Friday or Saturday; nicotine use is coded 1 = yes, 0 = no; other drug use is coded 1 = yes, 0 = no.

^*p < .01;

^**p < .001.