We’ve all heard about the liberal bias in the media, but Kevin Quinn (Harvard) and Daniel Ho (Stanford Law School) actually attempt to quantify this bias. Here’s how they do it according to their abstract:
Although central to understanding the role of the media, few quantitative measures of the political positions of media exist. We amass a new, large-scale dataset to shed light on this question. Collecting and classifying over 1500 editorials adopted by 25 major U.S. newspapers on 495 Supreme Court cases from 1994-2004, we apply an item response theoretic approach to place newspapers on a substantively meaningful and long validated scale of political preferences. Our results provide significant insights into the study of the media. We show that 18 of the 25 papers are more likely to the left of the median Justice for this period, but also considerable evidence that this may be an artifact of the liberalness of urban, elite, high circulation papers.
Here’s a ranking of justices and newspaper on the same scale and also the ranking of newspapers.
Here’s a link to the paper (ungated).