Dalton（2008）利用左右意識型態光譜建構「政黨極化指數」（party polarization index），有效偵測出一國政黨體系的實質運作與影響。但以該指數測量臺灣政黨體系的運作時，卻發現臺灣的政黨極化程度相對「穩定趨中」（stable and modest），與臺灣藍綠政黨衝突對立的政治現況格格不入。之所以如此，主要在於左右意識型態雖是歐美民主國家最重要的政治分歧，但甚少在臺灣的政治氛圍中出現，臺灣藍綠政黨的分歧主要存在於兩岸統獨議題。因此，本研究利用認知訪談及調查資料，分析臺灣民眾對左右派的認知，並調整 Dalton 的政黨極化指數，以統獨議題取代左右意識型態，檢測臺灣的政黨極化程度。研究結果發現，大多數的臺灣民眾確實不知道，甚至誤解左右派的意涵，以致 Dalton 的政黨極化指數無法真實反應臺灣政黨競爭的現況，反之，若以統獨議題取代左右意識型態，則可適切反應出臺灣政黨競爭的實際樣貌。這意味著在進行跨國比較分析時，除了追求指數建構的一致性外，仍須兼顧不同國家的實際政治氛圍，讓指數在適用上更具彈性及測量效度。

To assess interparty completion in democratic politics, Dalton (2008) constructed the “party polarization index” based on a left-right ideology. The partisan divide between the pan-Blue and pan-Green camps in Taiwan has been sharp and acute since the 1990s. This observed reality contradicts the stable and modest prediction based on Dalton’s index. To explain the difference, it is hypothesized that public opinion in Taiwan rests not on a left-right ideological continuum but on the issue of independence versus unification. This study utilizes cognitive interviews and survey data conducted in Taiwan to examine its citizens’ perceptions of left-right ideology in an attempt to adjust Dalton’s party polarization index. This research shows that most of Taiwan’s citizens are unfamiliar with, and sometimes misunderstand, the meaning of left-right ideology. The majority of the respondents cannot place themselves or identify the major parties’ positions on a left-right ideological continuum. The result indicates that Dalton’s party polarization index is inappropriate to examine Taiwan’s interparty competition due to the validity issue in measurement. By replacing the indicator of left-right ideology with that of the respondents’ positions on the unification versus independence issue, this study shows that Dalton’s index can better assess interparty competition in Taiwan. The implication of the findings from this study is that the index construction needs to adapt to different political contexts.