SNTV的政黨失誤類型之探討、測量與運用：以台灣立法院選舉爲例(1992-2004)

台灣是迄今民主國家中唯一仍使用單記非讓渡投票制度(single Nontransferable vote system, SNTV)以選舉國會議員的國家。就成本效益與比較選舉制度的角度來看，對其運作進行實證研究似乎沒有多大的價值。但是，站在公元2007年的台灣來研究SNTV在台灣國會議員選舉的現象，則有其特殊意義。本文旨在從測量的角度出發，對目前文獻歸納政黨在選舉所犯失誤類型，進行概念上的探討，並提出更精確的分類與測量。此外，本文將此新分類概念運用在對台灣國會選舉的測量，據以評估大黨的選舉表現，以及檢證在台灣尚未被具體解釋的大黨過度代表現象。本文主要的論點與研究發現如下：首先，傳統對政黨在SNTV選制下所犯錯誤的分類並不精確。同時，本文認爲從選舉結果定義政黨失誤類型比較能反映政治現實。其次，在四種政黨可能犯的失誤中，「不足提名且配票不均」對政黨的席次損失最大，其次爲「過度提名」。第三，根據本文所使用的四項指標，民進黨的選舉表現全部都優於國民黨。最後，針對大黨何以能享有過度代表的問題，本文發現，其他小黨與大黨的失誤是主要原因，選區規模並沒有解釋力。本文所提的政黨選舉失誤分類是否能有更廣泛的應用，值得有心之士一同努力探索。

關鍵字

失誤類型；席次紅利；最高可能獲得席次；單記非讓渡投票制度；選區規模

並列摘要

Taiwan is the only democratic country currently using Single Nontransferable Vote System (SNTV) to elect its national-level representatives. The main purposes of this article are, from the perspective of measurement, to explore the appropriateness of traditionally defined categories of errors committed by political parties in SNTV and suggest a more precise taxonomy. In addition, the author attempts to apply the advanced taxonomy to the measurement of Legislative elections and, accordingly, to evaluate the electoral performance of the two prominent political parties in Taiwan, i.e., the KMT and the DPP. Finally, the never-been-proved phenomenon of large parties' over-representation in Taiwan will also be tackled, using data gathered under the guidance of the taxonomy. The major arguments and findings of this article are as follows: first, the traditionally defined error committed by political parties is not precise. The author also finds it better to define errors from the perspective of electoral outcome rather than from the point of whether optimal number of candidate has been nominated. Second, political parties have to pay the highest price for committing error of ”undernomination and fail to equalize the vote.” Third, the DPP outperforms the KMT in all of the indicators used in this article. Lastly, but not the least, the key to the over-representation of large parties in SNTV lies in the errors committed by other large parties and small parties. District magnitude, however, does not play a role in explaining the phenomenon. It is the author's hope that the advanced taxonomy proposed by this article can help to shed light on many other issues in the literature.