The Media's Conditional Agenda-Setting Power: How Baselines and Spikes of Issue Salience Affect Likelihood and Strength of Agenda-Setting.

Whether agenda-setting effects occur and how strong they are appear to be strongly context-dependent. The baseline public and media salience of an issue and the extent of abrupt changes in salience have been mentioned as potential contingent conditions, but without any empirical follow-ups. First, this study demonstrates how agenda-setting effects unfold on a day-to-day basis, finding that only one fourth of the results (p <.05) are in line with the original agenda-setting hypothesis. Second, it tests how (a) the baseline intensity of public and media salience and (b) strong temporary increases ("spikes") in public and media salience impact the likelihood and strength of agenda-setting effects. Higher baseline public salience and stronger spikes in media salience systematically influence the likelihood and strength of agenda-setting effects. Agenda-setting scholars should systematically check, report, and possibly control for baseline intensity and spike momentum of media and public salience, which is also easy to implement. [ABSTRACT FROM AUTHOR]