Paul E. Peterson is the Henry Lee Shattuck Professor of Government at Harvard, the director of PEPG, and a senior fellow at the Hoover Institution. He is author or editor of numerous books, including The Education Gap: Vouchers and Urban Schools, with William G. Howell (Brookings, 2004 and 2006). He is coeditor (with Martin West) of No Child Left Behind? The Practice and Politics of School Accountability (Brookings, 2003). Mark C. Rom is a social science analyst at the U.S. General Accounting Office.