Mathematics discussions are important for helping students to develop conceptual understanding and to learn disciplinary norms and practices. In recent years, there has been increased attention to teaching prospective teachers to lead discussions with students. This paper examines the possibilities of designing a formative assessment that gathers information about prospective elementary teachers’ skills with leading problem-based mathematics discussions and makes sense of such information. A decomposition of the practice of leading discussions was developed and used to design the assessment. Nine first-year teachers who graduated from a range of different teacher education programs participated in the study. The findings reveal that our formative assessment works to gather information about teachers’ capabilities with leading discussions and that the associated tools support making sense of the information gathered. This suggests that such tools could be useful to support the formative assessment of the developing capabilities of prospective teachers.

数学讨论对于帮助学生发展概念理解和学习学科规范和实践很重要。近年来，越来越多的人开始关注教授未来的教师与学生进行讨论。本文探讨了设计形成性评估的可能性，该评估通过引导性的基于问题的数学讨论来收集有关未来小学教师技能的信息并理解这些信息。开发了领导讨论实践的分解，并用于设计评估。九名毕业于一系列不同教师教育课程的一年级教师参加了这项研究。调查结果表明，我们的形成性评估可以通过引导讨论来收集有关教师能力的信息，并且相关工具有助于理解收集到的信息。这表明此类工具可用于支持对未来教师发展能力的形成性评估。