Measuring the Partisan Behavior of U.S. Newspapers, 1880 to 1980

In this paper, we study newspaper partisan behavior and content, which we measure using coverage of and commentary on partisan activities, institutions, and actors. We use this measure to describe the levels of relative partisan behavior during the period 1880 to 1900, and to describe changes over the period 1880 to 1980. We find that, on average, newspapers were initially highly partisan, but gradually became less partisan over time. Importantly, we find as much change after the 1910s as before, which contributes to the existing literature that focuses on changes in the nineteenth and early twentieth centuries. We also investigate words and phrases that had negative or positive partisan connotations in particular periods. Finally, we examine whether some of the common hypotheses offered in the literature can account for the changes. The initial findings suggest that these explanations can only account for part of the decline.