This CAREER project explores the question, ?What constitutes expert teaching in the capstone environment?? This question examines the ?epistemology of engineering educators,? highlighted by the NSF-funded Engineering Education Research Colloquies as a core research area, in order to more effectively prepare current and future faculty to support student learning. This question will be answered in a four-phase mixed methods study consisting of 1) a national survey of capstone instructors informed by prior literature on both design education and teaching expertise, 2) interviews with selected instructors identified by the national survey, paired with surveys of the interview subjects? students; 3) in-depth case studies of expert instructors identified by the interviews and student surveys; and 4) development, implementation, and assessment of innovative online programs for graduate students and faculty to enhance teaching. This project builds on the growing body of research in two domains: design education and teacher expertise. Design education researchers have analyzed key design activities, compared practices of novices and experts, explored the role of reflective practice, examined problem definition, proposed instructional materials, and designed learning outcomes and assessments. At the same time, research on teacher expertise has identified practices associated with expert teaching in K-12, including domain knowledge, flexibility in adapting curricula, and effective monitoring of student learning. But researchers and faculty still lack a concrete understanding of teaching expertise in design education. The proposed CAREER project will make substantial contributions to the research in both domains, as well as provide a basis for future studies of design teaching and learning across the curriculum. The PI is experienced in the quantitative and qualitative research methods required for the study, and her prior research on design education provides a strong foundation for the work.