Research: Professor Diehl’s research focuses on how the opportunity structures and cultural logics of schools and school practices shape, and are in turn shaped by, social networks and relationships. He is especially interested in how these dynamics play out during school change efforts as reformers attempt to instantiate contested moral ideals about how teachers and students ought to live and learn together. His work has focused on issues such as: how differences in organizational contexts can explain varying levels of segregation, hierarchy and clustering in adolescent school networks; using streaming discourse data to model variation in classroom interactional order in terms of the dynamic relationship between activity structures and forms of talk; and a case study of a failed small school reform explained in terms of the difficulty not of changing teachers’ minds about their practice, but rather the structural and phenomenological nature of their relationships with each other and with their students.
Teaching: Professor Diehl's teaching has included Understanding Organizations – a course focused on theories of organizational functioning and organizational behavior. This course is a core course in the HOD undergraduate major. At the graduate level, Prof. Diehl has taught Theories of Inequality and Network Analysis.
Service: Professor Diehl is Chair of the HOD Colloquium Committee, a member of the Peabody College Curriculum committee, and serves as a reviewer for the American Journal of Sociology.
Community Engagement: Professor Diehl is Co-PI on a study of youth civic engagement and violence prevention (with Dr. Maury Nation) – a study actively working with Nashville schools, youth organizations and numerous youth-service agencies. This study engages youth groups and schools throughout Nashville, and collaborates with local community groups to reduce violence and improve youth outcomes.