Drinking on campus: self-reports and breath tests

Concern about excessive alcohol consumption by college students has been raised by surveys indicating that more than 40% of students are "heavy" drinkers. This definition is based on students' reports of consuming five or more drinks (four or more for women) on an occasion sometime during the past 2 weeks. The present survey examines the degree to which this 2-week 5+/4+ drink criterion characterizes a student's pattern of alcohol use, and whether a 5+/4+ criterion for a drinking occasion is a valid indicator of high blood alcohol concentration (BAC).

Students (N = 856, 70% male) were interviewed as they returned home between 10 PM and 3 AM. Students reported their drinking of the past 2 weeks and of the night they were interviewed, then provided breath samples to determine their BAC.

Among the students in the sample classified as "heavy" drinkers on the basis of self-reports, 49% had zero BAC on the night they were interviewed. Those who reported consuming 5+/4+ drinks the evening of the interview had a mean BAC <0.08%. The distribution of BACs in the entire sample showed 74.4% of students had a BAC of zero and 11.8% had a BAC <0.05%. Very high BACs (i.e., > or =0.15%) were rare (1.3%).

Self-reports of consuming 5+/4+ drinks on at least one occasion during the previous 2 weeks did not reliably identify a pattern of heavy drinking. Moreover, reports of 5+/4+ drinks on an occasion were not necessarily associated with high BACs.