PROJECT SUMMARY/ABSTRACT This application is for a supplement to the Mentored Research Scientist Development Award (K01 AA023849; PI: Braitman), directly necessary because of disruption due to the current coronavirus disease 2019 (COVID- 19) pandemic. Research activities under the original award included a series of four studies designed to refine the methodology, improve the efficacy of an electronic booster after computerized interventions. Research aims included to 1a) examine if feedback about harm reduction strategies strengthen the effects of personalized normative feedback alone in boosters emails (Study 1a - complete), 1b) examine if personal contact enhances the tailored feedback received (Study 1b - complete), 2) identify optimal timing of delivery for booster (Study 2 ? in progress), 3a) explore social mechanisms of change (across studies), 3b) examine the effects of interventions-plus-boosters when delivered to existing social networks (i.e., fraternities/sororities; Study 3 ? not yet started), and 4) examine potential moderators and mediators of reductions in alcohol use and related problems (across studies). Results will provide preliminary data for an R01 application. Prior to the pandemic shut down, data collection was complete for the first two studies in the sequence. Data collection for the third study was about to begin. However, on-site data collection for all studies involving human subjects was halted during March 2020 by the host institution due to the pandemic and related social distancing protocols. Although we have resumed data collection for Study 2 using virtual protocols (after a 9-month pause), examination of project aims is difficult due to the focus on social drinking. This has resulted in much slower enrollment than in previous studies. The extra funded year will allow for the final assessment window of Study 2 (9-month follow-up and data analysis) as well as all activities for Study 3. A projected timeline to complete all originally proposed research activities (complete Study 2 and conduct Study 3) and deliver on all project aims requires 12 additional months for the award, and additional funds are required to maintain the PI?s effort levels required by the mechanism. Training goals identified for the original award period included: 1) to broaden and strengthen her emerging adult alcohol use knowledge base, 2) to develop expertise in the enhancement and evaluation of boosters after interventions for college drinkers, 3) to increase her proficiency in Social Network Analysis, 4) to enhance scholarly productivity via secondary data analyses and manuscript preparation, and 5) to increase her grantsmanship, enlisting the mentorship of Drs. Kate Carey, Michelle Kelley, Cathy Lau-Barraco, Kayo Fujimoto, and Ken Leonard. Many of the training activities required attending in-person workshops and conferences which were cancelled due to the pandemic. Although some activities have transitioned online, the PI could not attend any in summer/fall of 2020 due to pandemic-related daycare closures. However, daycare is now reliably open and the PI plans to attend conferences and workshops during a funded extension year (if provided) so that all training activities are simply delayed and not cancelled.