Previous research has shown that the Meyerhoff Scholars Program (MSP) at the University of Maryland, Baltimore County is effective at increasing the number of underrepresented minorities (URM) in science, technology, engineering, and mathematics (STEM). While it is clear that comprehensive STEM programs, like the MSP, contribute to URM success in STEM, less is known about what mechanisms underlie program effectiveness, and which students are most likely to benefit from STEM interventions. As such, the current study explored how an important mechanism of influence in the MSP and a personal resource to students relate to psychological and academic adjustment. More specifically, psychological sense of community was examined as a mediator on the theorized relation between racial/ethnic identity (REI; e.g., high racial centrality and regard) and depression symptoms, research self-efficacy and science identity. Interactions between dimensions of REI (e.g., racial centrality, private racial regard, and public racial regard) were examined in their relation to these outcomes as well. Results demonstrated that there was no support for mediation or moderation as hypothesized. However, stronger racial/ethnic identity predicted stronger psychological sense of community within the MSP during summer bridge. Furthermore, students who reported stronger sense of community also experienced higher research self-efficacy and science identity at the end of their first year in college. The implications of the findings as well as the study limitations are discussed. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]