Working with Richard Ingersoll, professor of Education and Sociology at the University of Pennsylvania, the National Commission on Teaching and America's Future (NCTAF) examined and analyzed data from the "Schools and Staffing Survey" (SASS), the largest and most comprehensive source of data on teachers, gathered from a nationally representative survey conducted by the National Center for Education Statistics (NCES), the statistical division of the U.S. Department of Education. To better understand the impact of current teacher retirement systems, NCTAF and the Third Mile Group conducted a policy inventory of 14 states, which were selected to represent a balance of older and younger teachers in their workforces, inclusion or exclusion from the Social Security system, and geographic diversity. NCTAF's analysis of 20 years (six cycles) of SASS data clearly demonstrates an alarming reality: Almost half of the teaching workforce is made up of Baby Boomers who are at or near retirement. In 1976, when young Baby Boomers were flooding into the ranks of teaching, the average teacher age was 36; in 2007-08 it was 42 (SASS data). This country now has the oldest teaching workforce in more than half a century. Based on the realities uncovered and documented in this study, NCTAF has developed several recommendations to help schools, districts, and states develop 21st century workforce policies. These are: (1) Create state leadership coalitions to focus on developing comprehensive 21st century education workforce plans that go beyond recruitment and replacement strategies; (2) Align retirement policies with workforce and educational goals; (3) Examine and consider potential reforms to retirement plans; (4) Facilitate informed policy decisions by supporting additional research about the impact of early retirements on teaching quality, why individual teachers make the decisions they do, and how frequently teachers are leaving one district or state to teach in another district or state; (5) Create systems to identify and assess veteran teachers who are effective and interested in continuing to work in education; and (6) Pilot and fund new workforce development strategies and career paths. Five case studies are appended.