Hosting media bias : evidence from the universe of French broadcasts, 2002-2020

For democracies to function, voters need to be exposed to a variety of views, and media outlets play a key role in this process. Using novel data on hosts and guests appearing in millions of French television and radio shows over 20 years, this article shows that media largely differ in how much attention they devote to different political groups. We investigate the inner workings of media organizations leading to such differences, and in particular quantify the role played by hosts when it comes to deciding who to invite. Thanks to thousands of hosts moving across outlets, we first estimate a two-way fixed effects model and decompose the across-outlet variance in political group representation into three factors: (i) differences in host composition, (ii) host compliance with distinct editorial lines, and (iii) host sorting on outlets. We show that channel-level decisions and sorting largely explain across-outlet differences. Overall, hosts have little agency, but we document heterogeneity depending on their characteristics. To complement this analysis, we then study how hosts adapt to a major ownership-driven change in the editorial line, relying on a difference-in-differences framework. We find that hosts who stayed after the takeover largely complied with the new editorial line, but that many others left the acquired outlets. Our findings have important implications for the optimal regulation of the media industry and highlight the limitations of existing legislation on media pluralism.