The social norms marketing approach (SNMA) assumes that most individuals tend to conform to the perceived norms of the social groups in which they belong, but that in actuality these norms are often misperceived. This approach asserts that in situations concerning high-risk health behaviors (such as excessive drinking on college campuses), designing a social norms campaign to correct these misperceptions can prove highly effective in lowering the prevalence such behaviors. For the past 18 years, Michigan State University has been collecting data on students’ perceived and actual drinking behaviors to do just that. Before beginning a social norms campaign, data needs to be collected identifying that misperceptions around the behaviors in question actually do exist. Once this data is collected, social norms messages can be carefully constructed to correct these misperceptions. This article describes the methodology MSU used to gather the data necessary for this campaign, how their social norms messages are disseminated, and how the impact of social norms messaging is measured.