Project Abstract Strong demographic evidence shows that Native students are not integrating into STEM professional communities at the same rate as majority students. While Native people (Native American/Alaskan Native/Native Hawaiian) make up nearly 2% of the U.S. population according the most recent U.S. Census, they make up only about 0.01% of enrolled undergraduate students (NSF, 2014) and 3,014 (.5%) of the 601,883 enrolled graduate students in Science and Engineering (S&E) programs, with even smaller percentages persisting to faculty STEM careers (NSF, 2017). Why don't Native scholars with high interest in biomedical careers integrate into their STEM professional communities at rates equal to majority populations? At this time, most research regarding Native STEM scholars has been qualitative, involving in-depth interviews with those who persevere. To broaden the research, we propose to build on research regarding the Tripartite Integration Model of Social Influence (TIMSI) (Kelman,1958, 2006; Estrada et al., 2011), Native American culture, and integrative identity, to conduct a prospective propensity score matched longitudinal study to compare the short-, medium-, and long-term outcomes of three groups of emerging Native biomedical scholars (N=162). The groups include: (A) No Treatment Comparison group (matched Native scholars engaged in the American Indian Science and Engineering Society (AISES) community), (B) Modified Treatment group (matched Native scholars engaged in the AISES community + online professional development intervention), and (C) Full Treatment group (matched Native scholars engaged in the AISES community + complete professional development intervention). The primary aim of this study is to test the efficacy of an online intervention that “scales up” key aspects of an intensive professional development intervention relative to a control group. The second aim is to understand the mechanisms that explain the intervention effects. We will assess the degree to which key psycho-social factors (i.e., [i] efficacy, identity, and values [measures of integration into professional communities], [ii] Native scholars' professional-and-Native identity integration, and [iii] perceptions of communal value affordances in biomedical careers) mediate the relationship between the group differences and long-term integration into the professional community, greater career persistence, and higher rates of mentorship of future Native scholars. The hypothesis-driven design of this study will provide results that inform the biomedical community regarding factors and mechanisms that are most likely to influence and foster a sustained career in the biomedical research workforce. Further, this study provides a generalizable example of how to create added value from existing interventions (at significantly less cost than the parent intervention) for larger populations of students. Useful and meaningful findings will be made available in formats that a...