…experts and consumers agreed in aggregate about the quality of a book.
Amazon reviewers were more likely to give a favourable review to a debut author, which the Harvard academics said suggested that “one drawback of expert reviews is that they may be slower to learn about new and unknown books”.
Professional critics were more positive about prizewinning authors, and “more favourable to authors who have garnered other attention in the press (as measured by number of media mentions outside of the review)”.
Discovering that an author’s connection to a media outlet increased their chances of being reviewed by roughly 25%, and that the resulting review was 5% more favourable on average, the academics then investigated whether this was down to collusion.
They concluded that the bias was down to the media outlets aiming their reviews at their audience, “who have a preference for books written by their own journalists”, rather than collusion.