This self-study examined the learning that emerged from a change in teaching assignment coupled with self-initiated, teacher-led professional development in order to understand a high school science teacher's development as a teacher. The two participants in the study were the teacher/researcher, an experienced high school biology teacher who was taking up a new assignment teaching biotechnology, an advanced science course; and a first-year teacher assigned to teach biotechnology, who served as collaborator in the professional development and critical friend in the study. In order to uncover the teacher/researcher's learning and thinking, self-study of teaching practice methodology most clearly met the demands of the study. Data emerged from three research conversations and included transcripts of the conversations, artifacts from the participants' practices, notes from meetings, and memos. Data were analyzed using constant comparative methods and the understandings generated are grounded in the data. The study reveals shifts in teacher identity as the expert teacher takes up novice roles, the challenges encountered when teacher knowledge is insufficient for the teaching task, and the experienced teacher's need to return to a place of expertise when faced with a new teaching context. The study finds that (a) teacher identity shifts and develops in new teaching contexts, and teaching expertise facilitates expert identity development in such contexts; (b) expert teacher knowledge mediates novice-ness when experiencing new teaching contexts such as new teaching assignments; and (c) teacher-led professional development is a viable model for professional development experiences and can lead to increased teacher knowledge. The author suggests that (a) teachers are capable of determining what they need to learn and how they might best learn it in a professional development setting; (b) teachers' specific contexts should be honored when designing professional development, which should be practice-centered, and special attention should be given to developing specific subject matter knowledge, pedagogical content knowledge, and science knowledge for teaching; and (c) capable others should be included in collaborative professional development teams.



College and Department

David O. McKay School of Education; Teacher Education



Date Submitted


Document Type





qualitative research, professional development, professional identity, knowledge base for teaching, secondary school science