This multi-case qualitative study examined the factors that influenced an intern's learning about and implementation of a core practice, discussion-based teaching (DBT) during her two semesters of student teaching. Influenced by theories of how teachers learn about and enact core practices, comparative case studies were conducted involving two cases: (1) an intern and her first mentor teacher and (2) the same intern and her second mentor teacher. Specifically, the purpose of studying each... Show moreThis multi-case qualitative study examined the factors that influenced an intern's learning about and implementation of a core practice, discussion-based teaching (DBT) during her two semesters of student teaching. Influenced by theories of how teachers learn about and enact core practices, comparative case studies were conducted involving two cases: (1) an intern and her first mentor teacher and (2) the same intern and her second mentor teacher. Specifically, the purpose of studying each case was to understand (a) how the mentor and intern worked together to promote the intern's vision of DBT, (b) the ways in which opportunities for practice influenced the intern's enactment of DBT and (c) how the contextual and biographical factors influenced the intern's implementation and learning about DBT. Data sources included direct observations, semi-structured interviews, and audio-recorded conversations. Cross-case analysis suggested contextual factors were most influential in the intern's enactment of DBT, namely the opportunities for practice and learning community provided by her second mentor teacher. Evidence from the study shows interns can learn core practices such as DBT, but autonomy and exposure are not enough to build complex learning. Interns need to be placed with mentors who provide modeling, targeted feedback and collaboration, and regular opportunities for guided reflection around the core practice. Findings from the study have implications for teacher education programs as they prepare new teachers to enact core practices. Show less