This package provides material for supporting teachers in developing diagnostic teaching skills. It includes diagnostic assessment and instructional material for helping students who have difficulties in mathematics to identify and deal with their mistakes and misconceptions. These tools will enable teachers to help their students use common mistakes and misconceptions constructively in the classroom to promote more effective learning of mathematical concepts.

These materials, and the detailed suggestions for their use, focus on common difficulties within a number of mathematical topics. They support lessons that helps student identify their own and others' errors and, through discussion and reflection, understand and correct the misconceptions that underlie them.

This tool is designed for use by teachers, preferably working with a colleague or two. Since diagnostic teaching goes beyond traditional expository teaching, live professional development support is helpful. The parallel tool  Helping teachers gain diagnostic teaching skills is designed for such courses.

There is research evidence that shows, across a range of topics, that the diagnostic teaching approach leads to much better long term learning than standard "positive only" methods, which avoid analyzing and understanding misconceptions.

This is summarized in the strategy Gain diagnostic teaching skills and in
Askew, M. and D. Wiliam (1995). Recent Research in Mathematics Education 5-16. London.