在傳統公共政策研究中，對政策掮客（policy broker）、政策企業家（policy entrepreneur）或調停者（fixer）等角色在政策產出過程的中介功能，長久以來被視為是研究政策過程的核心議題之一，就現實的政策過程而言，也無法無視於其存在的價值。然檢閱相關文獻，公共行政學界對於政策中介角色的討論大多點到為止，缺乏分析工具之故，並未將這類行動者在政策場域（policy domain）中的角色與功能進行系統化的測量。本論文以台中市1986 年到1992 年間與都市發展有關的重要政策事件為分析案例，採用行動體系理論（actionsystem theory）的架構，蒐集台中市78個都市政策菁英參與8個重要都市發展事件的社會網絡資料，並透過社會網絡分析的中介中心性指標（betweenness centrality）、結構洞模型（structure holemodel）與橋樑者角色模型（brokerage role model），找出影響台中市重要都市發展事件的重要中介者與其特質。在理論與分析方法上，希望能為目前相關的研究議題提出一可行的分析工具；在實務的需求上，也希望能為台中都市發展政策過程中的政治管理提供具體可行的政策建議。

Although the recognition of policy brokers, policy entrepreneurs or fixers is a crucial determinant of policy output in the public administration and policy literature, little is known about its antecedents and how is it measured systematically. Using a unique dataset of 8 events and subsequent network relations among 78 political elites in the Taichung urban development domain before and after the lifting of martial law, this article applies social network analysis (SNA) to identify policy brokers and what their characteristics are by developing a conceptual framework about brokerage roles in policy processes. In theoretical development, this research is expected to demonstrate how the technique of SNA is helpful for not only identifying policy brokers but also showing how to measure different types of brokerage positions in policy processes. In practice, the analytical results increase the current understanding, in part, of how these political elites played their brokerage roles and enhanced their influence over policy-making and implementation in Taichung’s urban development domain from 1986 to 1992.