Project Summary Acute alcohol use and intoxication proximally increase the likelihood of college students’ intimate partner violence (IPV) perpetration underscoring the need to detect and intervene with alcohol-related IPV during critical drinking periods. Problematically, retrospective self-reported alcohol use has been the only method used to assess college students’ alcohol use in relation to IPV perpetration in their natural environment (e.g., ecological momentary assessment [EMA]). College students’ self-reported alcohol use underestimates their breath alcohol content (BrAC) by as much as 54% and is fraught with limitations; investigators’ ability to deliver and evaluate crucially-needed ambulatory alcohol-related IPV interventions (e.g., just-in-time interventions) is hindered by inaccurate alcohol assessment. Recent advancements in mobile breathalyzer technology allow investigators to remotely and objectively assess undergraduates’ alcohol use and intoxication in naturalistic settings. When paired with EMA of IPV, mobile breathalyzers offer a novel approach to strengthening alcohol-related IPV monitoring; no study has used portable breathalyzers to remotely assess alcohol use in relation to IPV. As a critical first step toward enhancing remotely-delivered alcohol-related IPV interventions, the overall objective of the proposed study is to determine the feasibility of using smartphone-linked, portable breathalyzers in conjunction with smartphone-based EMA to capture alcohol-related IPV episodes and contexts among heavy drinking college students with a recent IPV history. We will leverage our team’s established remote alcohol monitoring and EMA procedures to address three aims: The first aim is 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 is 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 is 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 will use smartphones to complete 5 daily (1 morning, 4 evening) self-reports of IPV and drinking context; smartphones will prompt 4 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. Results will provide EMA+ feasibility data to inform a future R01 using EMA+ with a large sample of couples to identify intra/interpersonal and contextual antecedents of college alcohol-related IP...