Abstract
Research on learner errors in mathematics education is beginning to focus on how
teachers can learn to identify and engage with the reasoning behind these errors. Research on
professional learning communities is beginning to show that they present powerful opportunities
for on-going teacher collaboration and learning. In this paper, I bring the two areas
of research together. Drawing on data from one professional learning community in the Data
Informed Practice Improvement Project, I show how teachers in this community came to
understand key concepts about learner errors and shifted their ways of talking about learner
errors. I identify three important shifts that the teachers made in their learning about learner
errors: from identifying to interpreting errors; from interpreting to engaging errors; and from
focusing on learner errors to focusing on their own knowledge. I argue that these three shifts
suggest a deepening of teachers’ thinking in relation to learner errors.
