Media Bias on Television and Its Determinants

Abstract

I investigate what factors determine the supply of news stories on the three major cable news channels — CNN, FOX News, and MSNBC. I use a novel dataset of chyrons, the text at the bottom of the screen, to examine what factors contribute to a story from a newswire like Reuters being relayed on each of the networks. I identify features of a story, such as its relevance, political valence, and whether the same story was reported on the other two channels as significant. This framework allows me to investigate media slant, which is conceptualized as the omission of important information or stories clashing with the political views of the audience (or the presumed political views of the channel). I find that media bias does indeed manifest itself through the omission of stories that have political significance and partisan value. I also investigate whether the identified media bias is demand-driven. I use an instrument for a decline in Fox News viewership on a given day — the existence of a NASCAR race, as the sport primarily attracts Republican viewers — to estimate whether a decrease in Fox News’ daily viewership prompts the network to omit stories harmful for the Republican party to a lesser extent. I find that NASCAR races significantly reduce Fox News’ viewership, but they do not lead to a change in the network’s omissive behavior.