How drunk am I? Misperceiving one's level of intoxication in the college drinking environment.

One effective event-level index that can assist in identifying risky intoxication levels among college students is blood alcohol concentration (BAC). Despite widespread exposure to BAC information, doubt exists as to whether American college students can accurately estimate their own BAC level or drinking behaviors while intoxicated. This study assessed whether students can accurately guesstimate their BAC level and drinking behaviors used to estimate BAC (eBAC) while drinking in social college settings. Participants (N = 225; 56.4% male) consisted of emerging adults attending either a 2- or 4-year college who had at least one alcoholic drink within the 2 hr before assessment. Participants were approached at night when returning from parties and/or alcohol-serving establishments. They completed an initial questionnaire, gave a breath sample to assess breath alcohol content, and then completed an online follow-up questionnaire within 48 hr of baseline assessment. Participants at lower levels of intoxication tended to slightly overestimate their BAC level, while those at higher levels tended to markedly underestimate their BAC level. In addition, discrepancies among breath alcohol content, guesstimated BAC, and eBAC were found as a function of gender. Lastly, differences in eBAC scores did not differ when drinking behaviors were obtained via in vivo versus retrospective methodology. Findings suggest that college students generally have difficulty assessing their BAC level and drinking behaviors while drinking in the college social setting. This study offers particular insight for research relying on estimates of BAC as well as interventions utilizing BAC education.