Extremity Bias in Online Reviews: The Role of Attrition

89 Pages Posted: 6 Sep 2019 Last revised: 23 Aug 2021

See all articles by Leif Brandes

Leif Brandes

University of Lucerne

David Godes

University of Maryland

Dina Mayzlin

University of Southern California - Marshall School of Business

Date Written: September 10, 2019

Abstract

In a range of studies across platforms, online ratings have been shown to be characterized by distributions with disproportionately-heavy tails. We focus on understanding the underlying process that yields such “j-shaped” or “extreme” distributions. We propose a novel theoretical mechanism behind the emergence of “j-shaped” distributions: differential attrition, or the idea that potential reviewers with moderate experiences are more likely to leave the pool of active reviewers than potential reviewers with extreme experiences. We present an analytical model that integrates this mechanism with two extant mechanisms: differential utility and base rates. We show that while all three mechanisms can give rise to extreme distributions, only the utility-based and the attrition-based mechanisms can explain our empirical observation from a large-scale field experiment that an unincentivized solicitation email from an online travel platform reduces review extremity. Subsequent analyses provide clear empirical evidence for the existence of both differential attrition and differential utility.

Keywords: online reviews, online word of mouth, field experiment

Suggested Citation

Brandes, Leif and Godes, David and Mayzlin, Dina, Extremity Bias in Online Reviews: The Role of Attrition (September 10, 2019). Available at SSRN: https://ssrn.com/abstract=3449159 or http://dx.doi.org/10.2139/ssrn.3449159

Leif Brandes

University of Lucerne ( email )

Lucerne
Switzerland

David Godes

University of Maryland ( email )

College Park
College Park, MD 20742
United States

Dina Mayzlin (Contact Author)

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

701 Exposition Blvd
Los Angeles, CA California 90089
United States
213-740-3360 (Phone)

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