臺灣與南韓「政黨選舉競爭穩定性」的比較分析：「選舉浮動性」的測量

Comparative Analysis on the Stability of Political Party Electoral Competition in Taiwan and South Korea: Measuring the Electoral Volatility

民主轉型後的臺灣與南韓已經逐步邁入民主鞏固階段，一套健全的制度化政黨體系的建立和形成乃是重要條件之一。其中，最優先的分析面向和觀察指標，即是兩國政黨選舉競爭是否已經具備足夠的穩定性和長期的規律性，具體表現在各政黨在換屆選舉中其浮動性高低程度的變化及消長。值此，本文研究主題，旨在比較分析臺灣與南韓政黨選舉競爭穩定性的高低程度及優劣表現，進而評估對政黨體系制度化的影響。為達成預期的研究目標，筆者將引用Pedersen 設計的「選舉浮動性」公式作為操作性測量工具，藉以計算臺灣與南韓政黨席次浮動及政黨得票浮動情況。根據比較分析後的結果，本文發現，臺灣的總體選舉浮動性較南韓為低，顯示臺灣政黨選舉競爭穩定性優於南韓，因此相對有利於政黨體系制度化的健全。

Taiwan and South Korea after democratization have gradually entered the consolidation phase of democratic development. The institutionalization of political parties, that is, to establish a well-developed party system, is one of the most important conditions for this phase. In both countries, the stability of the electoral competition of the political parties and the long-term regularity of the elections are taken as first primordial consideration among all the analysis models and the indicators, which can be measured by the range of the changes in the electoral volatility of the political parties. The purpose of this comparative analysis is to compare the stability and the performance of the electoral competition of political parties in Taiwan and South Korea as well as to evaluate its impact on the political party system institutionalization. In order to achieve the intended goal of the research, I will use the Pedersen Index of electoral volatility as the measuring tool to calculate the changes in voter volatility and seat volatility in Taiwan and South Korea elections. According to the results of the comparative analysis, I found that Taiwan has a lower aggregate volatility than South Korea, which means the stability of Taiwan's political electoral competition is higher than South Korea, thus leads to a better-institutionalized political party system in Taiwan.