The MSPinNYC2 project builds on a previous MSP-Targeted Partnership project (DUE-0412413, called the MSPinNYC), with new partners joining most of the original partners, to extend and deepen a promising program called the Peer Enabled Restructured Classroom (PERC), which was piloted during the earlier work. Core partners in the MSPinNYC2 partnership include Hunter College of the City University of New York (CUNY) as lead, the Brooklyn, Queens, Manhattan and Bronx High School Districts of the New York City Department of Education, and three other colleges in the CUNY system: York College, New York City College of Technology, and The Graduate Center. Additional partners include the College Now program at CUNY, the CUNY School Support Organization, and New Visions for Public Schools. The PERC program restructures 9th grade STEM courses to have 7 or 8 Teaching Assistant Scholars facilitate group work on a daily basis. TA Scholars are average-achieving, i.e., not honors, 10th graders who passed the course and the associated required state exit examination during the previous year and are concurrently trained in a TA Scholar course led by the same teacher as the 9th grade class. Pilot studies with PERC during the MSPinNYC project suggested that the program reduces failure rates, closes achievement gaps, and improves graduation rates. Based on lessons learned in the pilot studies with 9th and 10th grades in high schools in Manhattan and the Bronx, the MSPinNYC2 partnership is implementing PERC in nine high schools in Brooklyn and Queens, while expanding the program within three schools in Manhattan and the Bronx to incorporate all of grades 9-12 mathematics and science. A TA Scholar-to-College Pipeline supports TA Scholars throughout high school and prepares them for success in college. Students from PERC schools in all four boroughs who enter CUNY colleges are being mentored during the college freshman year, while STEM faculty and graduate students at the participating CUNY colleges are being supported to incorporate more student-centered pedagogies into freshman year STEM courses. PERC experiences are also being integrated into teacher education programs at the CUNY colleges. The research plan includes studying how PERC serves as a catalyst for school renewal, how the depth and sustainability of PERC implementation support scaling the innovation, how participation by teachers in PERC effects deep change within their practice, and how and why PERC experiences, as well as other forms of student support, lead to improved academic outcomes for students. The evaluation examines the fidelity of implementation and quality of the project's major components to provide formative evaluation, while the summative evaluation focuses primarily on assessing student achievement outcomes, their long-term academic success, and the overall diffusion of PERC into the secondary and post-secondary settings involved in the partnership.