Educational researchers widely acknowledge the promises and impediments of teachers’ collaborative sensemaking, illuminating the need to recognize additional resources that are salient for teachers within professional interactions. In line with this overarching goal, this study explores the role of mathematics teachers' previous professional experiences in their collaborative sensemaking. Theoretically, it is rooted in ecological theories of learning, highlighting that learning is always shaped by an interconnected set of environments. Empirically, it builds on data from a research–practice partnership with a professional development (PD) organization, where we used classroom video to support secondary mathematics teachers' teams in improving their practice. The analysis first portrays two video-based conversations to illustrate the potential of inviting and building on teachers’ previous experiences and resources to support their collaborative reasoning. Then, it looks across nine video-based conversations of the same two teams and systematically describes experiences and resources that teachers spontaneously reference through six categories: PD workshops, conferences, PD organizations, online resources, research and policy, and curricula. These categories provide a framework for designers and facilitators who want to take seriously the practice of acknowledging that teacher learning happens through a complex web of learning experiences. The study brings forth the affordances of taking a learning ecology perspective on teacher collaborative sensemaking as professional development (CSPD) and provides guidance for designing, facilitating, and analyzing CSPD conversations in ways that center on teachers’ prior knowledge and experiences.

教育研究人员广泛承认教师协作意义建构的前景和障碍，这表明需要认识到在专业互动中对教师来说很重要的额外资源。根据这一总体目标，本研究探讨了数学教师以往的专业经验在协作意义建构中的作用。从理论上讲，它植根于学习的生态理论，强调学习总是由一组相互关联的环境塑造的。从经验上看，它建立在与专业发展（PD）组织的研究实践合作伙伴关系的数据基础上，我们使用课堂视频来支持中学数学教师团队改进他们的实践。该分析首先描述了两个基于视频的对话，以说明邀请和利用教师以前的经验和资源来支持他们的协作推理的潜力。然后，它查看了同一两个团队的九个基于视频的对话，并系统地描述了教师通过六个类别自发引用的经验和资源：PD研讨会、会议、PD组织、在线资源、研究和政策以及课程。这些类别为想要认真对待承认教师学习是通过复杂的学习体验网络进行的实践的设计者和辅导者提供了一个框架。该研究提出了从学习生态学角度看待教师协作意义建构作为专业发展（CSPD）的启示，并为以教师先前知识和经验为中心的方式设计、促进和分析 CSPD 对话提供指导。