Teacher leaders take on a variety of roles within the classroom and school including resource provider, instructional specialist, curriculum specialist, classroom supporter, learning facilitator, mentor, school leader, data coach, and catalyst for change. They can serve formally through roles like department chair or instructionally coach, or informally by addressing problems or instituting new programs. Conditions that promote teacher leadership include a safe environment, supportive administrators, leadership training opportunities, and absence of resentment towards emerging leaders. Teacher leaders' impact can extend to school-wide policies, teaching and learning, and community relations.