柯文哲參選對2024年藍綠選票變動影響 ：以空間迴歸模型分析總統與不分區立委選舉

Abstract

2024年我國總統與不分區立法委員選舉，台灣民眾黨候選人柯文哲的參選對藍綠兩大黨的選票結構及政治版圖產生顯著影響，引發各界對政黨競合與選民行為變遷的關注。本研究從實證資料出發，結合「策略性投票」與「分裂投票」理論視角，深入分析柯文哲參選對民進黨與國民黨造成的選票排擠效果。 研究以台灣358個鄉鎮市區為觀察單位，運用空間迴歸模型進行分析，檢驗柯文哲參選是否顯著影響藍綠兩黨得票表現。此外，透過比較總統與不分區立委兩種不同選舉制度，觀察柯文哲及民眾黨的影響是否有差異。 研究結果顯示，柯文哲參選不論是總統或不分區立委選舉，所造成的排擠效應對民進黨特別顯著，雖國民黨也受到一定程度衝擊，但其程度相對較輕。而柯文哲對藍綠所造成的不利影響在總統選舉尤為顯著，有分裂投票現象，反映柯文哲個人魅力遠高於民眾黨的吸引力。 進一步分析發現，民進黨在青年人口比例較高地區的得票表現相對較差，顯示青年選民支持流失是其主要受挫原因之一，國民黨則受限於無法有效動員支持者外出投票。整體而言，民眾黨在本次選舉中扮演關鍵的擾動角色，不僅重塑傳統藍綠選票結構，更使選民行為趨向多元與策略性。

Based on empirical data, this study combines the theoretical perspectives of "strategic voting" and "split-ticket voting" to analyze in depth the vote-squeezing effect caused by Ko Wen-je’s candidacy on the Democratic Progressive Party (DPP) and the Kuomintang (KMT). Using Taiwan’s 358 townships, cities, and districts as units of observation and employing spatial regression models, the study examines whether Ko Wen-je’s candidacy significantly affected the vote shares of the DPP and KMT. Furthermore, by comparing the presidential and at-large legislative elections—two different electoral systems—the study observes whether the impact of Ko Wen-je and the Taiwan People’s Party (TPP) differs. The results show that Ko Wen-je’s candidacy produced a significant vote-squeezing effect on the DPP in both the presidential and at-large legislative elections. While the KMT was also affected to some extent, the impact was relatively milder. The adverse effect on both major parties was especially pronounced in the presidential election, where split-ticket voting was observed, reflecting that Ko Wen-je’s personal appeal far exceeded that of the TPP as a party. Further analysis reveals that the DPP’s electoral performance was relatively weaker in areas with a higher proportion of young people, indicating that the loss of support among young voters was a major reason for its setbacks. Meanwhile, the KMT was constrained by its inability to effectively mobilize its supporters to turn out to vote. Overall, the TPP played a crucial disruptive role in this election, not only reshaping the traditional KMT-DPP vote structure but also driving voter behavior toward greater diversity and strategic calculation.