乐观偏差是人们对于成功几率过于乐观的一种认知偏差。在工程建设领域，当过度乐观从个体层面通过沟通网络延伸至组织层面而形成集体乐观偏差时，将可能会造成严重后果。本研究拟结合社会心理学理论和网络科学理论，通过实证数据分析与智能主体仿真相结合的研究方法，揭示工程项目组织沟通网络拓扑结构对群体决策中有害集体乐观偏差的影响机理并加以控制。具体包括：（1）通过实证研究分析工程项目组织沟通网络拓扑结构对集体乐观偏差的影响；（2）构建工程项目组织沟通网络中多层级智能主体仿真模型；（3）基于构建的仿真模型，通过大样本情景模拟探索沟通网络拓扑结构与集体乐观偏差间的关系；（4）结合机制设计理论，提出有效降低工程项目有害集体乐观偏差的控制机制。研究成果可以为我国工程建设项目的科学决策与管理提供理论依据和实践参考。

Optimism bias is a cognitive bias of people to be overly optimistic about the chance of success. In the construction field, the collective optimism bias at the organizational level could be harmful to projects when it is evolved from the individual level via organizational communication network. Based on social psychology theories and network science, this research aims to examine the impact of organizational communication network topology on the collective optimism bias of construction projects by using an integrative methodology of empirical study and Agent-Based Modeling (ABM), which includes (1) identifying the impact of organizational communication network topology on the collective optimism bias of construction projects via empirical study; (2) constructing a multi-level agent based model; (3) conducting large sample explorative simulation experiments to examine the causal relationship between communication network topology and the collective optimism bias of construction projects; and (4) developing an effective and efficient mechanism to control the harmful collective optimism bias of construction projects. The findings of this research are expected to provide the theoretical underpinning and the practical reference for the scientific decision making and management of construction projects in China.