DP16147 Bias in expert product reviews
|Author(s):||Jan C. van Ours, Ben Vollaard|
|Publication Date:||May 2021|
|Programme Areas:||Industrial Organization|
|Link to this Page:||cepr.org/active/publications/discussion_papers/dp.php?dpno=16147|
Hard evidence on bias in expert reviews and its consequences for ratings is rare. This holds particularly true for conflicts of interest that are thought to be common in non-blind product reviews but are not readily observable: ad hoc relationships between reviewers and producers. We present a textbook case of a long-running expert product review in the food service industry for which we happen to know the reviewer's conflict of interest: being affiliated to one particular producer. As is typical, only insiders were aware of the possible source of bias in the review. The review resembles other non-blind tests of product quality. We obtained detailed data to map the consequences of the conflict of interest. We find evidence of a sizable bias in the reviewers' ratings. Our findings suggest that reviewers' ad hoc relationships with producers, often dismissed as `coming with the job', can be very harmful.