Project SPACE: Testing Daily Text Messages to Reduce Alcohol Use and HIV Risk Behavior

Project SPACE is a micro-randomized trial evaluating the proximal effects theory-based text messages on alcohol use and sexual HIV risk behaviors among HIV-negative young adult men at the day-level. At baseline, all participants will complete GamePlan, an existing brief online sexual health program. During the subsequent 8-week intervention period, participants will complete a brief morning assessment of the preceding day and will be randomized each afternoon, with equal probability, to receive concrete (\"how\"), abstract (\"why\"), neutral control, or no afternoon intervention messages. Participants will also complete pre- and post-intervention measures. The effects of GamePlan are not being separately evaluated in this study.