Diane Ravitch is Research Professor of Education at New York University and a historian of education. She serves on the board of the Core Knowledge Foundation, Common Core, the Albert Shanker Institute of the American Federation of Teachers, and Common Good. She is an honorary life trustee of the New York Public Library and a former Guggenheim Fellow. From 1991 to 1993, she served as the United States Assistant Secretary of Education, and from 1997 to 2004, she was a member of the National Assessment Governing Board, which oversees the National Assessment of Educational Progress. Find Diane Ravitch's blogs at dianeravitch.net and at http://blogs.edweek.org/edweek/Bridging-Differences/.