"does Media Concentration Lead to Biased Coverage? Evidence from Movie Reviews" Does Media Concentration Lead to Biased Coverage? Evidence from Movie Reviews *

Fueled by the need to cut costs in a competitive industry, media companies have become increasingly concentrated. But is this consolidation without costs for the quality of information? Concentrated media companies generate a conflict of interest: a media outlet can bias its coverage to benefit companies in the same group. We test empirically for bias by examining movie reviews by media outlets owned by News Corp.–such as the Wall Street Journal–and by Time Warner–such as Time. We find a statistically significant, if small, bias in the review score for 20th Century Fox movies in the News Corp. outlets. We detect no bias for Warner Bros. movies in the reviews of the Time Warner outlets, but find instead some evidence of bias by omission: the media in this group are more likely to review highly-rated movies by affiliated studios. Using the wealth of detail in the data, we present evidence regarding bias by individual reviewer, and also biases in the editorial assignment of review tasks. We conclude that reputation limits the extent of bias due to conflict of interest, but that nonetheless powerful biasing forces are at work due to consolidation in the media industry. ∗Preliminary, do not cite without permission. Ivan Balbuzanov, Tristan Gagnon-Bartsch, and Xiaoyu Xia provided excellent research assistance. We thank audiences at Brown University, Boston University, and UC Berkeley for very helpful comments. We also thank Bruce Nash for access to data from the-numbers, as well as helpful clarifications about the industry.