Teaching matters: A longitudinal study of mathematics teachers’ knowledge growth

Teaching a particular subject provides rich opportunities for teachers to develop subject-specific knowledge and skills, especially for those who are in the early years of their career. Yet supporting evidence is scarce regarding the extent to which knowledge and skills teachers could gain from their teaching experience. This study aims to address this gap by collecting data from a from a national sample of 207 novice mathematics teachers for three years in a row to explore the development of two elements of teachers' pedagogical content knowledge (PCK) of mathematics: (1) knowledge of students' mathematical thinking and (2) knowledge of mathematics teaching. By using linear growth modeling to analyze the data derived from teachers' analyses of videos clips of mathematics classes, we found that teachers increased both elements of PCK, albeit at different rates. Further, the growth of these two important elements of PCK were associated with different teacher-related factors. Having a robust knowledge of mathematics played a key role in teachers' learning of students' mathematical thinking, whereas having a credential in mathematics teaching played a role in the development of teachers’ knowledge of mathematics teaching.