近年來，深綠選民經常認為是陳水扁總統在個人危機，或是民進黨在選戰中的主要訴求對象，因而凸顯了深綠選民的重要性。本文主要的目的在於探討深綠選民應該如何測量及定義，以及他們是否真的是泛綠陣營選票的主要來源。作者根據台灣意識、台灣人政權以及政黨認同的概念，建構三個不同的指標，以測量及定義深綠選民。分析結果發現：以指標的表現而言，三個指標各有其優缺點，但在TEDS2005M 的資料中，以台灣人政權指標的整體表現較佳。三個指標所定義的深綠選民，投票給泛綠候選人的比例都有九成左右，而且台灣意識指標及政黨認同指標所分別定義的深綠選民比例，都達全體選民的五分之一，顯示他們是夠份量的「鐵票部隊」。另外，三個指標所定義的深綠選民之主要特徵是：年紀偏長（50 歲以上）、教育程度較低（國初中為主）、本省閩南人、農林漁牧業或藍領階級者。

Conventional wisdom holds that when President Chen Shui-bian faces personal crises, as well as in the Democratic Progressive Party’s (DDP) election campaigns, Chen and the party always appeal to the so-called “deepgreen voters” for support, such that these voters factor prominently in determining election outcomes. The purpose of this paper is to define and measure deep-green voters, and also to examine whether the support of deep-green voters is vital for the pan-green parties. The author creates three indices to measure deep-green voters, based around the concepts of Taiwanese consciousness, Taiwanese regime, and party preference. The results show that the three indices have different strengths and weaknesses, but that the Taiwanese regime index performs best in the TEDS2005M survey. The data also shows that the probability that a voter identified from these indices as deep-green votes for pan-green candidates is approximately 90%. Moreover, the number of deep-green voters identified from the Taiwanese consciousness and Taiwanese regime indices make up about one fifth of the electorate. The results indicate that the deep-green voters are vital and staunch supporters of pan-green parties. As identified by the three indices, deep-green voters tend to have the following characteristics: over 50 years old, less-educated (junior high school or less), Bensheng-minnan ethnicity, and lower class.