本研究旨在探討民眾的選舉參與，是否因為年齡不同而產生顯著的差異？以往學術文獻大多假設年齡和選舉參與之間為簡單的線性關係，本文假設，依據「生命週期效應」（life-cycle effects）的觀點，年齡因素對於選舉參與的效應，應呈現正向但遞減的趨勢。為驗證此項研究假設，作者增列「年齡平方項」做為研究變數，藉由「2005年至2008年『台灣選舉與民主化調查』四年期研究規劃（IV）：民國九十七年總統大選民調案」（簡稱為TEDS 2008P）面訪調查資料，以「雙變數交叉分析」（cross-tabulation analyses）、「有序勝算對數模型」（ordered logit models），以及「勝算對數模型」（logit model），檢證年齡和「年齡平方項」對於選民在2008年總統選舉競選期間從事政治活動和投票參與的影響。實證結果顯示，年齡與選舉參與之間雖然呈現顯著的正向關係，但隨著年齡的增長，民眾從事政治活動的增加幅度則呈現下降趨勢。在結論中，作者摘述研究發現，並認為「年齡平方項」得成為政治學者進行實證分析時常設的社會人口特徵變數，藉此更清晰地描繪出民眾政治參與的整體分配特性。

This study employs socio-demographic characteristics as explanatory variables for political participation, especially exploring the impact of age on electoral participation. In contrast to previous research based on a linear relationship between age and electoral participation, this study adopts the theoretical framework of life-cycle effects and hypothesizes that the correlation is positive but clearly nonlinear. Viewed in this light, the study takes advantage of the national survey of "Taiwan's Election and Democratization Study" and examines the effects of "age square" on campaigning activities and voting participation in the 2008 presidential election. The methodology adopted in this study involves cross-tabulation analyses, ordered logit models, and logit models respectively. As hypothesized, the results reveal that electoral participation increases steadily with age, but participation among the oldest age group declines presumably because these people are in poorer health and less mobile physically. In the conclusion, we summarize the major findings and propose some research suggestions for further investigations.