Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
We characterize the optimal editorial positions of the media in a model in which the media influence both voting behaviour and party policies. Political parties are less likely to choose partisan policies when more voters consume informative news. When there are two media outlets, each should be slightly biased relative to its audience in order to attract voters with relatively extreme views. Voter welfare is typically higher under a duopoly than under a monopoly. Two media outlets under joint ownership may provide more diverse viewpoints than two independent ones, but voter welfare is not always higher. Copyright 2008, Wiley-Blackwell.