This study was funded by the NIH (AA030858, PI: Brem). This study had two aims: The first aim was to examine the feasibility and acceptability of using portable breathalyzers paired with EMA to investigate the association between BrAC and IPV among heavy drinking, previously-aggressive college students. The second aim was to determine if breathalyzer-derived BrAC is a stronger predictor of different forms of IPV perpetration than is self-reported alcohol use, and whether there are gender differences in these associations. Our exploratory aim was to examine contexts (e.g., where, when, and with whom one drinks) in which alcohol-related IPV events occur, which will help optimize EMA delivery in future alcohol-related IPV studies. Across 30 consecutive days, 100 heavy drinking college students with an IPV perpetration history used smartphones to complete 4 daily (1 morning, 3 evening) self-reports of IPV and drinking context; smartphones prompted 3 evening BrAC submissions to a smartphone-linked portable breathalyzer (plus event-triggered reports) to provide the most rigorous, accurate, and ecologically-valid assessment of alcohol-related IPV to date. Primary study results have been submitted for publication.