Young people need a combination of academic skills and other key mindsets and behaviors to succeed in school and become healthy, employed, civically engaged adults. In recent years, there has been growing interest in the relationship between academics and social-emotional learning (SEL)--a broad set of competencies that includes, for example, self-efficacy, growth mindset, and interpersonal skills. This report describes a portion of work from an innovative SEL-focused research-practice partnership between the Student Success Network (SSN) and the Research Alliance for New York City Schools. The project investigated two central research questions: (1) How, if at all, does students' growth in SEL contribute to improved academic performance? Which SEL competencies contribute the most?; and (2) To what extent does the relationship between SEL and academic growth differ by student subgroup? Is growth in SEL a stronger contributor to academic outcomes for middle or high school students? For 9th graders? For students with disabilities? Do students from more disadvantaged neighborhoods benefit more or less? This report explores the answers to these questions, drawing on data for nearly 6,000 middle and high school students in New York City. With the goal of informing programming, as well as future research, the report raises some fundamental questions about how SEL is defined and taught, as well as the overall purpose of schooling (i.e., a narrow focus on academics, vs. a broader vision for developing young adults). The report recommends actions that schools and youth programs can take to further explore and build on the insights from the partnership's work to date. [This report was co-authored by the Student Success Network (SSN). For the technical appendix, see ED615831.]