Co-planning stands as a critical aspect of Achievement First's culture of collaboration. In addition to weekly coaching sessions and co-planning meetings at the grade and department levels, Achievement First high school teachers participate in a number of regular sessions that underscore the teaching-as-team-sport mentality on which the school's success depends. Among them, weekly professional development sessions and regular "Data Days" during which the entire school community assembles to crunch assessment data and evaluate school-wide progress toward achievement benchmarks and a shared vision of excellence. In between, the broader Achievement First network -- 20 schools throughout Brooklyn and urban Connecticut -- offers a rich landscape to collaborate with other teachers in the same subject area and grade level, exchange lesson plans and recommit to the organization's no excuses, gap-closing mission.