. Author manuscript; available in PMC: 2009 Mar 31.

Published in final edited form as: Psychol Addict Behav. 2005 Sep;19(3):296–302. doi: 10.1037/0893-164X.19.3.296

Table 4.

Between- and Within-Group Effect Sizes for Changes on Five Outcome Variables Following Interventions

	Baseline to 3 months			Baseline to 6 months
	Within group			Within group
Variable	BMI	AE	Between group	BMI	AE	Between group
No. drinks per week (square root)	0.25	0.33	0.23	0.15	0.18	0.01
Frequency of binge drinking episodes	0.18	0.22	0.08	0.39	0.52	0.01
Typical BAC	0.37	0.11	0.26	0.67	0.19	0.04
Peak BAC	0.46	0.27	0.15	0.48	0.15	0.01
RAPI score	0.90	0.29	0.04	1.11	0.07	0.39

Note. BMI = brief motivational intervention; AE = alcohol education; BAC = blood alcohol content; RAPI = Rutgers Alcohol Problem Index. Effect sizes can be described as small (0–0.30), medium (around 0.30–0.80), or large (greater than 0.80); medium and large effect sizes are in boldface type.