Roughly half a million U.S. teachers either move or leave the profession each year--attrition that costs the United States up to $2.2 billion annually. This high turnover rate disproportionately affects high-poverty schools and seriously compromises the nation's capacity to ensure that all students have access to skilled teaching, according to this Alliance report. To curb turnover--especially among new teachers--the report recommends a comprehensive induction program comprised of multiple types of support, including high-quality mentoring, common planning times, and ongoing support from school leaders. Also included is the appendix: The Cost of Teacher Attrition by State (2008-09) (by Richard Ingersoll, University of Pennsylvania). [This report was written in collaboration with Ann Maddock and Liam Goldrick.]