Parents, teachers, and government officials agree that America's schools must be reformed. However, new research suggests that most reforms will not work without closer attention to one critical resource--time. This document presents findings of a study conducted by the Rand Institute on Education and Training, which found that any reform takes time to formulate, plan, implement, and institutionalize. Because teachers must give first priority to classroom teaching, they must accommodate the new demands of reform into their already tight schedules. Reform conducted on the fringes of the school day, however, will never amount to fundamental change. Four principles for creating the time that staff members need are offered: (1) readjust priorities by removing old demands and resisting other reforms that divert time and attention; (2) provide time and resources for teachers; (3) recognize change as a long-term process requiring patience; and (4) create shared time for groups to work together. Drawing on these four principles, specific implications for the roles of the following groups are identified: state education agencies and legislatures should apply a realistic time frame; teachers' unions should advocate a wider range of job descriptions for teachers; foundations and business partners should extend their support over a number of years; school boards should make staff planning time a routine part of the school calendar; school administrators should institutionalize common planning time and provide staff; and teachers and other staff should abandon some existing commitments, and use time slots appropriate to the purpose. (LMI)