College students' estimation and accuracy of other students' drinking and believability of advertisements featured in a social norms campaign.

Social norms campaigns, which are based on correcting misperceptions of alcohol consumption, have frequently been applied to reduce college students' alcohol consumption. This study examined estimation and accuracy of normative perceptions for students during everyday drinking occasions. Students who reported having 4 or fewer drinks underestimated the percentage of other students who had 4 or fewer drinks, while those who drank 5 or more drinks overestimated the percentage of other students who had 5 or more drinks. Believability of advertisements featured in social norms campaigns also played a crucial role in this process. Those who believed the ad more closely estimated alcohol consumption by their peers while ad believability moderated the relation between drinking behaviors and accuracy.