Table 5.

Between groups effect sizes comparing Control and TLFB/control conditions to the Basic BMI and the TLFB/Basic BMI conditions

	1-Month Assessment				12-Month Assessment
	Control versus		TLFB/Control versus		Control versus		TLFB/Control versus
	Basic BMI	TLFB/Basic BMI	Basic BMI	TLFB/Basic BMI	Basic BMI	TLFB/Basic BMI	Basic BMI	TLFB/Basic BMI
Drinks per week	.29	.32	.21	.26	.22	.03	.31	.11
Drinks per drinking day	.41	.41	.24	.24	.20	.17	.35	.30
Heavy drinking frequency	.27	.32	.21	.25	.05	−.02	.36	.25
Peak BAC	.22	.33	.33	.44	.11	.32	.39	.57
RAPI	.39	.52	.24	.37	.12	.22	.39	.50

Note. Values in the table represent Cohen’s d calculated with pooled standard deviations. Small effect sizes (.15–.39) are underlined; medium effect sizes (.40–.74) appear in bold. BMI = brief motivational intervention. TLFB = Timeline Followback interview; BAC = blood alcohol concentration; RAPI = Rutgers Alcohol Problems Index.