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Human Communication


Political advertising is one of the dominant media for reaching voters. Previous metaanalyses (Allen & Burrell, 2002; Lau, Sigelman, Heldman, & Babbitt, 1999) found little or no net benefit to negative versus positive ads. However, this finding does not reveal whether ads have effects (both or neither could be persuasive). A meta-analysis revealed that political spots increased issue knowledge, influenced perceptions of the candidates’ character, altered attitudes, and affected candidate preference; influenced agenda-setting, and altered vote likelihood (turnout). One moderator variable was detected: The effect size for learning was larger for studies of students than non-students; however, the effect size for both sub-groups was significant. On the other hand, political ads had larger effects on attitudes for non-students than students.


Originally published in Human Communication, Volume 10, No. 4 (2007).

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