The Market for Fake Reviews

46 Pages Posted: 20 Aug 2020

See all articles by Sherry He

Sherry He

University of California, Los Angeles (UCLA), Anderson School of Management

Brett Hollenbeck

University of California, Los Angeles (UCLA) - Anderson School of Management

Davide Proserpio

Marshall School of Business, University of Southern California

Date Written: July 31, 2020

Abstract

We study the market for fake product reviews on Amazon.com. These reviews are purchased in large private internet groups on Facebook and other sites. We hand-collect data on these markets to characterise the types of products that buy fake reviews and then collect large amounts of data on the ratings and reviews posted on Amazon for these products, as well as their sales rank, advertising and pricing behavior. We use this data to assess the costs and benefits of fake reviews to sellers and evaluate the degree to which they harm consumers. The theoretical literature on review fraud shows there exist conditions when they harm consumers and conditions where they function as simply another type of advertising. Using detailed data on product outcomes before and after they buy fake reviews we can directly determine if these are low-quality products using fake reviews to deceive and harm consumers or if they are possibly high-quality products who solicit reviews to establish reputations. We find that a wide array of products purchase fake reviews including products with many reviews and high average ratings. Soliciting fake reviews on Facebook leads to a significant increase in average rating and sales rank but the effect disappears after roughly 1 month. After firms stop buying fake reviews their average ratings fall significantly and the share of one-star reviews increases significantly, indicating fake reviews are mostly used by low quality products and are deceiving and harming consumers. We also observe that Amazon deletes large numbers of reviews and we document their deletion policy.

Keywords: Fake reviews, online platforms, e-commerce, fraud, consumer protection

JEL Classification: L81, L15, L51, K13

Suggested Citation

He, Sherry and Hollenbeck, Brett and Proserpio, Davide, The Market for Fake Reviews (July 31, 2020). Available at SSRN: https://ssrn.com/abstract=3664992 or http://dx.doi.org/10.2139/ssrn.3664992

Sherry He

University of California, Los Angeles (UCLA), Anderson School of Management ( email )

110 Westwood Plaza
B411
Los Angeles, CA 90049
United States

Brett Hollenbeck (Contact Author)

University of California, Los Angeles (UCLA) - Anderson School of Management ( email )

110 Westwood Plaza
Los Angeles, CA 90095-1481
United States

Davide Proserpio

Marshall School of Business, University of Southern California ( email )

701 Exposition Blvd
Los Angeles, CA Los Angeles 90089
United States

HOME PAGE: http://faculty.marshall.usc.edu/Davide-Proserpio/

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