The Data Informed Practice Improvement Project (DIPIP), was hosted at the Wits School of Education, University of the Witwatersrand, Johannesburg, South Africa.DIPIP aimed to create a context in which ‘critical friends’ (post graduate students and district facilitators) worked with school teachers on data which provides evidence of learners’ performance. In this work the critical friends and the teachers discussed and analysed (inter alia) how the learner data fits with everything else they know from research and experience, how to identify learners’ errors and misconceptions when they arise during teaching and in assessment, how to address these in teaching and in assessment and how to reflect with learners on their mathematical thinking both verbally and in writing.

The project was structured to examine teacher’s interpretive skills on learners’ errors and misconceptions and their application of knowledge gained about the interpretation of learner errors and misconceptions in their classrooms. In the context of this project, the concept of mathematical knowledge for teaching focused on teachers’ understanding of errors and misconceptions evident from learners’ performance on the ICAS test. In so doing the project aimed to develop the diagnostic judgement of teachers.