合作问题解决（CPS, Collaborative problem solving）能力是未来公民的基本素养之一，既是社会发展的时代需求，也是学生发展的实际需要。项目式学习（PBL, Project-based learning）以合作为重要工作方式、以问题解决为关键目的，是一种能有效培养学生 CPS 能力的学习方式。从理论层面来看，合作问题解决能力的内涵和测评框架已被广泛讨论、研究和应用，学者们对项目式学习的内涵、设计原则和基本实施环节也已达成一定的共识，但很少关注 PBL 中培养 CPS 能力的策略。从实践层面来看，全国各地中小学展开了丰富的 PBL 尝试，但多数项目对学生 CPS 能力的培养仍隐匿于活动设计与实施之中。因此，需要进行基于设计的研究以探索在小学项目式学习中培养合作问题解决能力的策略和方法，促进相关理论在实践中的应用。本研究参考 ATC21S 和 PISA2015 的能力框架，结合小学生的心理发展特点，将 CPS 能力解构为合作维度的共享理解、分工配合、组织调节和问题解决维度的问题理解、信息管理、任务调节。

本研究遵循 PBL 的设计原则，基于 CPS 能力框架设计了嵌入入项、制定计划、产品制作和出项四个阶段的学习活动和支架，将评价量规贯穿于整个项目过程，共设计和实施了“改造学校游泳池”和“音乐节嘉年华场地规划”两次项目式学习，并通过对定性和定量数据的分析揭示了学生 CPS 能力的变化。两轮 PBL 有效提升了学生的 CPS 能力，且学生在不同阶段有不同的合作问题解决表现，证明了本研究活动设计策略的有效性，建议教师基于能力框架和 PBL 各阶段的学习目标设计相应的学习活动、支架和评价量规，注重过程性和表现性评价，关注高学段学生的元认知能力，尤其是计划和反思能力的培养。

Collaborative problem solving (CPS) is one of the essential skills for future citizens. It is both a societal demand and a practical necessity for student development. Project-based learning (PBL) emphasizes collaboration as a crucial working method and problem-solving as a key objective, making it an effective learning approach to foster CPS competency. From a theoretical perspective, the connotation and assessment framework of CPS have been widely discussed, researched, and applied. Scholars have also reached a certain consensus on the meaning, design principles, and basic implementation stages of PBL. However, there has been little focus on strategies for developing CPS abilities within PBL. From a practical perspective, primary and secondary schools in China have engaged in extensive PBL initiatives, but most which still lack explicit cultivation of CPS skills. Therefore, it is necessary to conduct design-based research to explore strategies for developing CPS competency in PBL in primary education, promoting the practical application of relevant theories.

In this study, the ability frameworks of ATC21S and PISA 2015 are utilized, taking into account the psychological development traits of primary school students. CPS competency is deconstructed into two dimensions: collaboration dimensions, including shared understanding, task division and coordination, and organizational regulation; and problem-solving dimensions, including problem understanding, information management, and task regulation. Following the design principles of PBL, this study designs learning activities and scaffolding for four project stages: immersion, planning, production, and presentation, based on the CPS ability framework. The assessment criteria are integrated throughout the entire project process. Two project-based learning were designed and implemented, named Transforming the School Swimming Pool and Music Festival Venue Planning. The study analyzed and triangulated qualitative and quantitative data to understand changes in CPS abilities. The learning activities in the two PBL experiences included team formation activities such as Perfect Circle team building, peer assessment, collaborative reflection and revision of collaboration rules. The learning scaffolding included tools like W-H charts, workflow diagrams, and individual and team characteristic analysis charts and tables. The two rounds of PBL effectively enhanced CPS abilities, demonstrating the effectiveness of the activity design strategies used in this study. Students exhibited different collaborative problem-solving performances at different PBL phases. The study suggests that teachers could design learning activities, scaffolding and assessment tools based on the CPS framework and learning objectives for specific PBL stages, emphasizing both process-oriented and performance-based assessments. It is crucial to pay attention to foster metacognitive abilities in grade 5 and grade 6, particularly the planning and reflection skills.