Good News For People Who Rely on Movie Reviews

According to a new working paper by Stefano DellaVigna and Johannes Hermle, movie reviews aren’t biased by media ownership. The paper is called “Does Conflict of Interest Lead to Biased Coverage? Evidence from Movie Reviews.” Here’s the abstract:

Media outlets are increasingly owned by conglomerates, inducing a conflict of interest:  a media outlet can bias its coverage to benefit companies in the same group.  We test 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 use a matching procedure based on reported preferences to disentangle bias due to conflict of interest from correlated tastes.  We find no evidence of bias in the reviews for 20th Century Fox movies in the News Corp. outlets, nor for the reviews of Warner Bros.  movies in the Time Warner outlets.  We can reject even small effects, such as biasing the review by one extra star (out of four) every 13 movies.  We test for differential bias when the return to bias is plausibly higher, examine bias by media outlet and by journalist, as well as editorial bias.  We also consider bias by omission:  whether the media at conflict of interest are more likely to review highly-rated movies by affiliated studios.  In none of these dimensions do we find systematic evidence of bias.  Lastly, we document that conflict of interest within a movie aggregator does not lead to bias either.  We conclude that media reputation in this competitive industry acts as a powerful disciplining force.

Here is some previous DellaVigna research that we’ve highlighted; and here’s our podcast on media bias generally.


Matt Boyd

Is this also true with food review apps? Or are the companies that are hired to boost reputations have an effect on the reviews? Does this create a bias? If so, what variable would be established by Yelp, Urbanspoon,etc. to correct this in the future?

Isabel McCann

The, often freelance, person who writes the movie reviews is a long way down the chain of command from the proprietor and exists in a different atmosphere. I suspect that the proprietor would like to see a bias but waters this down when he (and it usually is a he) communicates with senior editors due to ethical and practical concerns, and natural shyness. The senior editors in turn communicate the watered down bias which is communicated to them in a further watered down way (for the same reasons, and because they have less skin in the game), and by the time you get to the movie critic, little preference for bias is being communicated at all. You see much more bias in leader articles, which are written by someone in direct touch with the proprietor.