In Washington, D.C., and Tulsa, Okla., districts whose efforts are supported by the Wallace Foundation, principal supervisors concentrate on bolstering their principals' work to improve instruction, as opposed to focusing on the managerial or operational aspects of running a school. Supervisors oversee fewer schools, which enables them to provide principals with the coaching and supervision they've lacked in the past. Principal supervisors in these districts now spend at least 70% of their time inside schools. Both districts have seen improvements as a result of this new focus on teaching and learning.