Implementation support strategies such as professional development (PD) are pivotal in guaranteeing the assistance that teachers need to enact mathematics teaching innovations and to secure lasting change. Within large-scale efforts an important issue for researchers is to understand how to design and put into effect these implementation support strategies. Although some work has been done to examine the challenges of implementing PD to advance the enactment of mathematics teaching innovations in new school settings, little is known about the multiple challenges novice facilitators face when providing PD for fellow teachers in their local districts and communities. In this paper we report on a 3-year long study that examined how a novice facilitator learned to deal with these challenges and become confident in his new role. Drawing on Graven’s (Educational Studies in Mathematics 57(2), 177–211, 2004) expanded model of learning, a case study and an interpretative approach are used to investigate a novice facilitator’s process of becoming confident. The findings provide evidence that becoming confident is part of an ongoing process of learning through (1) experiencing or constructing new meanings for problem solving as an instructional approach; (2) doing or enacting the instructional approach; and (3) engaging in the core PD practices. Recommendations for the education of PD facilitators in large-scale initiatives are provided.

专业发展 (PD) 等实施支持策略对于确保教师实施数学教学创新和确保持久变革所需的帮助至关重要。在大规模的努力中，研究人员的一个重要问题是了解如何设计和实施这些实施支持策略。尽管已经做了一些工作来研究实施 PD 以推动新学校环境中数学教学创新的实施所面临的挑战，但对于新手辅导员在为当地地区和社区的其他教师提供 PD 时面临的多重挑战知之甚少。在本文中，我们报告了一项为期 3 年的研究，该研究检查了新手引导者如何学会应对这些挑战并对其新角色充满信心。借鉴 Graven 的（数学教育研究 57(2), 177–211, 2004）扩展的学习模型，案例研究和解释方法用于调查新手引导者变得自信的过程。研究结果提供证据表明，变得自信是持续学习过程的一部分，方法是 (1) 作为一种教学方法，体验或构建解决问题的新意义；(2) 执行或制定教学方法；(3) 参与核心 PD 实践。提供了在大规模倡议中对 PD 促进者进行教育的建议。研究结果提供证据表明，变得自信是持续学习过程的一部分，方法是 (1) 作为一种教学方法，体验或构建解决问题的新意义；(2) 执行或制定教学方法；(3) 参与核心 PD 实践。提供了在大规模倡议中对 PD 促进者进行教育的建议。研究结果提供证据表明，变得自信是持续学习过程的一部分，方法是 (1) 作为一种教学方法，体验或构建解决问题的新意义；(2) 执行或制定教学方法；(3) 参与核心 PD 实践。提供了在大规模倡议中对 PD 促进者进行教育的建议。