Using British research related to the Open University's Postgraduate Certificate in Education (OU PGCE), a preservice teacher education program, this paper considers how open and distance learning (ODL) programs are evolving quality assurance systems and procedures across a range of elements, including student teacher assessment. The paper explores how high-quality provision and outcome standards of students are assured in a high-volume, highly dispersed program with over 2,000 school-based contexts for practice each year. Section 1 presents an overview of some ODL teacher education programs. Section 2 discusses quality assurance issues for ODL preservice teacher education. Section 3 focuses on assessment (an example of high quality in an open learning preservice education program). Section 4 examines issues related to improving program quality. The paper concludes that three factors (course materials with their common structure; the competence model with its open, shared, and moderated assessment; and the program support and monitoring network of the Open University) all combine to maintain the quality and integrity of the course and qualification. An appendix presents an OU PGCE competence and professional qualities model. (Contains 7 figures and 20 references.) (SM)