Despite growing evidence on the popularity, the coverage, and the effects of partisan news media in the U.S., missing is a more fundamental understanding of how potential political bias manifests in partisan media coverage. We propose a comprehensive framework examining (a) the prevalence of political news that is positive toward the in-party (in-party affinity) versus negative toward the out-party (out-party hostility), accounting for key factors shaping these reporting strategies, and also attend to (b) user engagement with these different reporting strategies. Analyzing 1,011,911 Facebook posts from 50 major partisan outlets in the U.S. from 2010 to 2020 with ensemble models integrating Gemini, Llama, and DistilBERT, we show that partisan media criticized the out-party more than praised the in-party. This pattern was influenced by the changing political and media environment, party power distribution, and ideological extremity of the media outlet. Users were more likely to share and comment on posts criticizing the out-party than those praising the in-party, but less likely to react to such content (e.g., like, love, haha, angry); higher levels of reactions, but not shares or comments, in turn, predicted increased posting of out-party negative news posts.
Yu et al. (Fri,) studied this question.