This paper studies the channels through which political television advertising influences individuals' voting decisions. Scholars are interested to learn whether advertising primarily persuades people to change their choices of candidates or mobilizes people to vote. I find that advertising does both: about 60% to 70% of advertising's effect is persuasion, and 30% to 40% of it is mobilization. Advertising's effects are stronger on those who did not plan to vote for a major-party candidate. To decompose the impact into its components, the present paper estimates a multinomial probit model that permits analysis of decisions of turnout and candidate choice jointly in a Markov chain framework. In contrast to most studies that estimate the effects of aggregated exposure to advertising on voters' choices on Election Day, I study how advertising influences peoples' monthly voting intentions leading up to Election Day. In the context of the 2008 presidential election, the magnitude of the advertising effect is not large enough to overcome John McCain's significant deficit, but it potentially could have changed the outcomes of other close elections such as those in 2000 and 2016.

本文研究了政治电视广告影响个人投票决定的渠道。学者们有兴趣了解广告主要是说服人们改变他们对候选人的选择还是动员人们投票。我发现广告两者兼而有之：大约 60% 到 70% 的广告效果是说服，30% 到 40% 是动员。广告对那些不打算投票给主要政党候选人的人的影响更大。为了将影响分解为其组成部分，本文估计了一个多项 Probit 模型，该模型允许在马尔可夫链框架中联合分析投票率和候选人选择的决策。与大多数估计广告暴露对选举日选民选择的影响的研究相比，我研究广告如何影响人们在选举日之前的每月投票意向。在 2008 年总统大选的背景下，广告效应的幅度不足以克服约翰麦凯恩的巨额赤字，但它可能会改变其他势均力敌的选举，例如 2000 年和 2016 年的结果。