Co-location is the controversial policy of having multiple schools share a single school building. CEE's new report, "The Effects of Co-Location on New York City's Ability to Provide All Students a Sound Basic Education," is based on site visits and interviews with staff in close to 50 New York City public schools. It provides evidence to suggest that co-location exacerbates some schools' existing resource deficiencies and creates further constraints to their ability to fulfill all students' constitutional educational rights. It concludes with some recommendations for the mayor and the chancellor.