Personalized learning is often equated with individual learning using technology. Yet for many students, learning on their own may not effectively meet their needs. The aim of this study is to explore racial differences in experiences and benefits associated with collaboration. The authors collected data from a variety of sources for students, teachers, and classrooms within four racially diverse high schools that emphasized both personalization and collaboration. The sample included 892 students, 138 teachers, and 30 classrooms. The qualitative analyses identified emergent themes from focus groups and interviews, and the quantitative analyses examined associations among opportunities for collaboration, classroom experiences, and outcomes, testing whether these associations differed for Black students versus White students. The authors found that, for all students, reports of high-quality collaboration were strongly associated with positive classroom experiences and mind-set/dispositional outcomes such as motivation, engagement, and self-efficacy. Moreover, high-quality collaboration was strongly associated with students' perceptions of personalization--and personalization, in turn, was strongly associated with outcomes. At the same time, focus group discussions revealed that Black students perceived less relevance in collaborative activities, more frequent experiences of exclusion and marginalization, and lower support from teachers during collaborative group work than did non-Black peers. Findings from this study suggest that collaborative experiences could be among the factors that contribute to positive changes in the academic trajectories of Black students, particularly when these opportunities reflect high-quality features. Thus, schools and educators aiming to address equity through personalization should consider increasing opportunities for high-quality collaboration. American Institutes for Research (AIR) conducted this study as part of the Research Collaborative's initial cycle of research. The team at AIR worked alongside fellow scholars, educators, and policymakers to investigate the impact of specific student-centered practices and then translate their findings for cross-sector audiences. This report represents their work over the past two years as they designed, tested, and revised teacher practices as part of a networked improvement community and examined how student agency impacted academic outcomes. [For the executive summary, see ED592101].