在多數政治環境中，決策是集體行動的結果，也是政策產出最重要的影響因素之一，探究誰統治（who governs)?誰掌控政策產出？或是決策過程中的權力分佈（power distribution)如何系統化的測量與圖像化（visualisation)?影響權力分佈的因素為何？一直是古老、核心且無可避免的研究議題，對上述研究問題的重視也導致學術界與實務界對於測量權力路徑的需求。但過去對於集體決策的研究，都難以清楚從質、量化的方法，掌握決策權力運作的機制與特質。本論文以理論發展為始，並以1998年到2012年間四個重要的健保財務改革政策為討論個案，透過文獻資料，深度訪談蒐集相關研究資料，企圖從結構分析（structure analysis)的角度，以社會網絡分析法（social network analysis)為分析工具，並運用程度中心性指數（degree centrality index)及圖像化的方式，對健保政策近十年來的改革進行影響力機制的分析，並探討權力分佈是鑲嵌政策參與者何種互動結構之中，以及是否對政策產出的結果造成影響。在理論的企圖上，本文展示了社會網絡分析法作為一親近現實決策權力分佈分析工具的可能性；在實務的企圖上，本文也透過社會網絡分析法，對健保政策複雜的治理機制進行一糸統化的分析，並提出相關的政策建議。

Policy-making process, without any doubt, can be always translated into a language of power. In order to explore how policy is made, numerous scholars in Politics, Public Administration, and Policy Science have attempted to find the best approach to measure power distribution and its impact factors in policy-making processes. However, none of these approaches can help us to grasp the constant changes of “power map” systematically. In Sociology, or more specifically, Political Sociology, the development of social network analysis technique seems to shed the light to supplement the gap. Based on social network analysis, power distribution can be understood by the perspectives of not only relation between actors but also position in a bounded network structure. This study attempts to follow this idea to study the power distribution and its impact factors of Taiwan’s National Health Insurance (NHI) sustainability between 1998 and 2012. In regard to research methods, in-depth interviews have been used to collect data. In conclusion, first, for those who are searching for “localised power map” to analyse policy processes in Taiwan, this study is a primary but useful beginning for applying social network analysis. Second, with regard to the most powerful actors of Taiwan’s NHI domain, there is no doubt that the alliance between the public sectors and the providers show critical influence in the policy making process.