Competition and Ideological Diversity: Historical Evidence from US Newspapers
研究了20世纪初美国报纸市场中竞争如何影响意识形态多样性，发现竞争增强了多样性但市场供给不足，并指出最优竞争政策需考虑新闻市场的双边性。
We study the competitive forces which shaped ideological diversity in the US press in the early twentieth century. We find that households preferred like-minded news and that newspapers used their political orientation to differentiate from competitors. We formulate a model of newspaper demand, entry, and political affiliation choice in which newspapers compete for both readers and advertisers. We use a combination of estimation and calibration to identify the model's parameters from novel data on newspaper circulation, costs, and revenues. The estimated model implies that competition enhances ideological diversity, that the market undersupplies diversity, and that optimal competition policy requires accounting for the two-sidedness of the news market.