Dynamic Media Bias

• In Event: Bias, Media Bias, and Nothing but Bias

Abstract

Ideological media bias is increasingly central to the study of politics. Yet, past literature has assumed that the ideological bias of any outlet, at least in the short term, is static and exogenous to the political process. We challenge this assumption. We use longitudinal data from the Stanford Cable News Analyzer (2010-2020), which reports the screen time of various political actors on cable news, and quantify the partisan leaning of those actors using their past campaign donation behavior. Using one instantiation of media bias---the mean ideology of political actors on a channel, i.e., visibility bias---we examine weekly as well as within-day estimates of media bias. We demonstrate that media bias is highly dynamic and responsive to audience feedback even in the short term. Our findings have important implications for the study of political communication and the political economy of mass media.

Authors

• Eunji Kim, Columbia University

• Yphtach Lelkes, University of Pennsylvania

• Josh McCrain, University of Utah