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Learning More from Political Communication Experiments: The Importance of Pretreatment Effects (WP-11-09)

James Druckman and Thomas Leeper

Research on political communication effects has enjoyed great progress over the past twenty years. A key ingredient underlying these advances is the increased usage of experiments that demonstrate how communications influence opinions and behaviors. Virtually all of these studies pay scant attention to events that occur prior the experiment – that is, “pretreatment events.” In this paper, Druckman and his co-author explore how and when the pretreatment environment affects experimental outcomes. They present two studies – one where they control the pretreatment environment and one where it naturally occurred – to show how pretreatment effects can influence experimental outcomes. The researchers argue that, under certain conditions, attending to pretreatment dynamics leads to novel insights including: a more accurate portrait of the pliability of the mass public, and the identification of potentially two groups of citizens – what they call malleability reactive and dogmatic.

James Druckman, Payson S. Wild Professor of Political Science, and Faculty Fellow, Institute for Policy Research, Northwestern University

Thomas Leeper, PhD candidate, Political Science, and Graduate Research Assistant, Institute for Policy Research, Northwestern University

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