15.3. FACTORS CORRELATED WITH BIAS
Having constructed an intuitive and replicable measure of media bias, it is natural to
explore the determinants of this bias, or at least to identify variables that are significantly
correlated with bias. The ideological stances of media outlets should be viewed as equi-
librium phenomena, i.e., as outcomes of the interaction of demand-side and supply-side
factors. Thus, our discussion is closely connected with
Chapter 14, which focuses on the
theoretical aspects of media bias.
15.3.1 Demand-Side Factors
Gentzkow and Shapiro (2010) show that their index of politically slanted language is pos-
itively and significantly correlated with the partisan leanings of the Zip codes where each
newspaper is sold. To measure the ...