民調在競選中的角色：以二○○○年台灣總統大選中「未表態選民」為例

Abstract

本文探討兩千年總統大選期間「未表態選民」的形成與變遷的因素，尤其是探討興票案作為一個選舉醜聞（scandal），對於三位主要候選人──陳水扁、宋楚瑜與連戰──支持度的影響。透過一個時序性總體變遷模型的建立，以民調的加總資料（aggregate distribution）為分析對象，加上控制測量工具的差異後，本文發現興票案的確轉移了較多的宋楚瑜支持者為不確定的「未表態選民」，相對地，連戰的支持者則變得較為穩定，至於陳水扁的支持者則不受影響。本研究基本上印證了常識的看法，即宋楚瑜的支持者因興票案而流失，連戰則因此產生支持度鞏固的效果。此外，對於選舉實務的貢獻則是，提供一個分析總體民調資料變遷的方法，以預測趨勢與事件效果，有助於競選決策的形成。

This article develops a model of forming non-response in consecutive polls when there is uncertainty about candidate’s character due to a scandal event. The first section provides a theoretical clarification on the intentions and effects of campaigning and shows that both uncertainty reduction and expectation are indispensable for individual voters to reveal their preferences. In this way, polling is an efficient tool to send signals and make noise during campaigning. The data analysis suggests that the scandals do have an effect and that candidate James Soong suffers from the increasing number of non-response voters.