單記非讓渡投票選舉制度下的個人與政黨取向：一個混合洛基模型

Abstract

過去選舉制度的研究相信，在複數選區單記非讓渡投票選制（SNTV）的選舉，政黨與個人因素對選民的投票抉擇「應該」相當重要。然而，現有選舉行為的文獻並未就此一信念予以嚴格檢驗。本文證據顯示，雖然這兩類因素都有顯著影響，「政黨」因素遠比「個人」因素更強而有力。概括來看，在選民的投票抉擇當中，政黨因素最為關鍵；在同黨候選人之間，個人因素可用以決勝負。再者，政黨因素與個人因素也有交互作用。不同的政黨脈絡下，選民對個人因素重要與否的判斷有所不同，表面上看似屬於候選人的個人投票，其實政黨因素的考量可能影響很大。研究方法上，本文提出混合洛基模型（mixed logit），作為SNTV投票抉擇模型的適當統計工具，所檢驗的民調資料係針對1992年至2004年台灣五次立委選舉的調查。

There are reasons to believe that both partisan and personal factors should be important in the voting decision in SNTV elections, but this has not been rigorously tested in previous literature. This paper presents evidence that both types of factors have significant impacts, but partisan factors are much more powerful than personal factors. In general, partisan factors dominate the candidate vote choice, and personal factors serve primarily as tiebreakers among candidates from the same party. Moreover, the importance that voters place on personal factors varies in different partisan contexts, and there is generally a partisan logic to these varying weights.Methodologically, this paper proposes mixed logit as an appropriate tool for modeling voting choices in SNTV and examines data from the five legislative elections in Taiwan from 1992 to 2004.