Social Support for Drinking comprised two variables: the mean drinking status (from 1=abstainer to 5=heavy drinker) of the persons in the participant's social network plus the mean of those persons' reactions to the participant's drinking (from 1 = “left the room” to 5 = “encouraged” drinking). Behavioral Support for drinking was the proportion of heavy drinkers in the participant's social network (i.e., modeled drinking behavior). Attitudinal Support for drinking was calculated by taking the mean of the reactions to drinking of the top four persons on the participant's list of important people. Internal reliabilities of the Social Support for Drinking and the Attitudinal Support for Drinking variables exceeded α = .70 at all follow-ups.
