The interplay of institutional reform efforts and the role of external actors (public officials and agencies, private sector entities) have brought about changes in teacher education programs, e.g., fifth-year program innovations. A naturalistic case study approach was used to investigate structural and substantive changes in four extended teacher education programs that had made structural changes in the past 5-17 years. Each program moved from a 4- to a 5-year plan, increased academic requirements and field experiences, and made stronger connections to the client schools. From analysis of the data some generalizations can be made: (1) those programs that have changed and prevailed have demonstrated change in curriculum grounded on a well articulated knowledge base; and (2) the curriculum changes reflect a major change in priorities due to an interaction of internal and external actors and circumstances. The results of the case studies demonstrate that the impetus for change comes from a change in priorities, but that the interrelationships between the various publics may ultimately predict the direction of teacher education in a given institution. Five graphs and a bibliography are attached. (AMH)