Table 1.

Means (and standard deviations) and within-person effect sizes (Cohen’s d) on outcomes by condition

	Follow-up			Effect size at follow-up
Variable	Baseline M (SD)	1 month M (SD)	6 month M (SD)	1 month	6 month
Full sample
Drinks per week
PDF	10.75 (13.82)	9.46 (12.37)	8.20 (10.83)	-0.31	-0.48**
EDU	10.59 (13.85)	8.41 (11.37)	9.08 (13.18)	-0.41**	-0.25
Peak BAC
PDF	.054 (.082)	.044 (.070)	.034 (.065)	-0.30	-0.53**
EDU	.053 (.088)	.032 (.061)	.038 (.071)	-0.58**	-0.35*
Drinkers
Drinks per week
PDF	13.60 (14.25)	11.68 (13.01)	10.31 (11.32)	-0.43*	-0.56**
EDU	13.92 (14.35)	10.77 (11.94)	11.38 (13.63)	-0.53**	-0.39*
Peak BAC
PDF	.067 (.087)	.054 (.075)	.042 (.071)	-0.36	-0.57**
EDU	.068 (.095)	.039 (.066)	.047 (.074)	-0.74**	-0.46*
Heavy drinkers
Drinks per week
PDF	16.96 (14.89)	15.13 (13.88)	12.71 (14.89)	-0.39	-0.68**
EDU	19.64 (15.57)	15.05 (13.03)	16.05 (15.85)	-0.64**	-0.42
Peak BAC
PDF	.088 (.093)	.070 (.081)	.054 (.080)	-0.44*	-0.75**
EDU	.107 (.105)	.062 (.079)	.070 (.089)	-0.92**	-0.69**

Notes: Alcohol-related problems are not reported because of differences in timeframes the consequences were assessed. At baseline, participants reported consequences experienced over the past 6 months, and at 1-month and 6-month follow-ups, participants reported consequences experienced over the past month. PDF = personalized drinking feedback; EDU = educational information; BAC = blood alcohol concentration (estimated).

^*p < .05;

^**p < .01.