An innovative team teaching model has taken hold in the largest school system in Mesa, Arizona, US, and now has expanded to one third of its 82 schools. Five years ago, faced with high teacher turnover and declining student enrollment, Westwood High School’s leaders worked with professors at Arizona State University’s teachers college to pilot a classroom model that lets teachers share large groups of students and rotate between big group instruction, one-on-one interventions, small study groups or whatever the teachers as a team agree is a priority that day. Each morning, Westwood teams spend two hours hashing out a personalized program for each student on their shared roster. ASU started investigating team teaching about six years ago, feeling its unusual staffing structure could help revitalize teachers, and early results from Mesa show it benefits both teachers and students. Students in team-based classrooms have better attendance, earn more credits toward graduation and post higher GPAs.