現任者優勢指的是現任議員在選舉中，因現任者的身份，而享有的 競選優勢。我國自2008年起，立委選舉發生兩大變革，一是選制由 過去的單記不可讓渡投票制改爲小選區相對多數制，二是人數減半。 因此變革，之後的現任者將能嚇阻高素質挑戰者的投入，及擁有更 多資源從事選區服務，從而使其具備強大的競選優勢。本研究使用 「台灣選舉與民主化調查」的面訪資料，以多層次巢狀勝算對數模型 分析後發現，在2012年的立委選戰中，現任立委享有相當顯著地競 選優勢，但此現象在2004年的選戰中卻不明顯。由於此現象對我國 民主發展有不利影響，吾人宜及早因應。

Incumbency advantage is the benefit of being an incumbent in an election. In 2008, the legislative electoral system in Taiwan was switched from single non-transferable voting to first-past-the-post voting. The number of seats was also halved from 225 to 113. After this change, incumbents were able to deter quality challengers from running, and they could also deploy more resources in constituency services than their predecessors. Therefore, incumbents in the 2012 legislative election should have more advantage than those in the 2004 election. The author used a survey data set from Taiwan's Election and Democratization Study. The empirical results indicated that being an incumbent could offer statistically significantly advantage in the 2012 election, but incumbency advantage was not statistically significant in the 2004 election. In light of the damage of incumbency advantage in the U.S. democracy, we should seriously consider measures to mitigate the damage.