AI 中文总结
本文研究有偏新闻来源的竞争对信息与福利的影响，提出共同信念筛选标准，发现对立有偏来源误报成本足够高时，新增该来源可提升接收者福利，竞争或改善决策但未必具社会益处。
AI 中文摘要
我们研究当有偏新闻来源可以承担成本地歪曲事实时，这类来源间的竞争如何影响信息与社会福利。垄断和竞争市场结构均存在大量均衡。我们提出一种适用于两者的基于共同信念的筛选标准，使福利比较成为可能。在经筛选的结果下，当对立有偏来源面临足够高的误报成本时，增加该来源可提升接收者的福利。竞争约束在位者的同时引入自身的若干扭曲。更好的信息未必提升总福利，而垄断者的扭曲建议却可提升总福利。竞争可改善决策却未必具有社会益处。
英文摘要
We study how competition among biased news sources affects information and welfare when sources can misrepresent facts at a cost. Monopolistic and competitive market structures admit many equilibria. We develop a common belief-based selection criterion that applies to both and makes welfare comparisons possible. Under the refined outcomes, adding an oppositely biased source improves the receiver's welfare when that source faces sufficiently high misreporting costs. Competition disciplines the incumbent while introducing a few distortions of its own. Better information need not increase total welfare, and distorted advice from a monopolist can raise total welfare. Competition may improve decision-making without being socially beneficial.
