Teachers need to be taught how to collaborate. When the Stamford (Conn.) Public Schools introduced PLCs in the district's 20 schools, they learned of the four roles that districts play when implementing PLCs systemwide: 1) Districts must involve teachers and administrators in developing and leading the PLC process, 2) they must teach administrators and teachers how to work together effectively in PLCs, 3) they must show how PLCs fit into the district's improvement process, and 4) they must support schools according to their unique needs.