Bharat Anand, Rafael Di Tella and Alexander Galetovic

Two aspects of media bias are important empirically. First, bias is persistent: it does not seem to disappear even when the media is under scrutiny. Second, bias is conflicting: different people often perceive bias in the same media outlet to be of opposite signs. We build a model in which both empirical characteristics of bias are observed in equilibrium.The key assumptions are that the information contained in the facts about a news event may not always be fully verifiable, and consumers have heterogeneous prior views (“ideologies”) about the news event. Based on these ingredients of the model, we build a location model with entry to characterize firms’ reports in equilibrium, and the nature of bias. When a news item comprises only fully verifiable facts, firms report these as such, so that there is no bias and the market looks like any market for information. When a news item comprises information that is mostly nonverifiable, however, then consumers may care both about opinion and editorials, and a firm’s report will contain both these aspects—in which case the market resembles any differentiated product market. Thus, the appearance of bias is a result of equilibrium product differentiation when some facts are nonverifiable.We use the model to address several questions, including the impact of competition on bias, the incentives to report unpopular news, and the impact of owner ideology on bias. In general, competition does not lead to a reduction in bias unless this is accompanied by an increase in verifiability or a smaller dispersion of prior beliefs.