College students' responses to a 5/4 drinking question and maximum blood alcohol concentration calculated from a timeline followback questionnaire.

Objective: Many surveys employed to study college drinking ask whether students have had a five-drink (for men) or four-drink (for women) episode in one sitting at least once during the previous 2 weeks to indicate risky or heavy episodic drinking. However, some researchers have questioned the predictive validity of the 5/4 measure. This study tested whether such students attained extremely high blood alcohol concentrations (BACs) during the previous 30 days.