Skip to Content

Darla Moore School of Business


The Dark-Side of User Reviews: The First-Review Effect and Incentivized Reviews

Nov. 19, 2018

Have you ever noticed that the same product can have wildly different online reviews on two different platforms? Assistant marketing professor Sungsik Park aims to explain this phenomenon in his research paper “The Fateful First Consumer Review.”

If consumers believe that a product’s online reviews are an accurate reflection of its quality, how and why are the reviews for identical products so varied? Park said that this discrepancy has something to do with the first review a product receives.

“When you think about it, for the reviews to be posted, someone has to buy the product,” Park said. “If a product happens to receive a very negative first review, no one will buy the product, so no reviews will be posted. So that initial bias in the negative reviews cannot be corrected by subsequent reviews.”

In an empirical study, Park and his coauthors matched the same vacuum cleaner on Amazon and Best Buy and analyzed the difference in the number of reviews and the ratings as a function of the very first review the vacuum cleaner received.

The study found products that received a negative first review suffered a loss in both the average ratings and the number of reviews across subsequent reviews, even after three years.  Furthermore, it showed that, even in the absence of fake reviews, the information in user reviews could be easily distorted.

Park’s latest research project focuses on different types of incentivized reviews. Seller initiated incentivized reviews occur when a company provides a free product to a consumer, and in return, the consumer posts a review of the product online.  

“It turns out that these reviews are systematically more positive than organic reviews,” Park said. “95% of incentivized reviews are rated 4 or 5, compared to only 70% of the organic reviews are positive for exactly the same product.”

Companies that use seller incentivized reviews tend to have long-term relationships with the consumers that receive their free products. This seller-consumer relationship might lead to biased reviews.

However, in 2016, Amazon banned seller-incentivized reviews. As an alternative, the company kept Amazon Vine, a program where consumers still receive free products in exchange for posting reviews – but Amazon selects the participants, and the reviewers have no contact with the original seller. This mechanism virtually shuts down the possibility that sellers induce reviewers to post upward biased reviews.

Park’s findings have shown that these Amazon Vine reviews, or platform-initiated reviews, were not biased at all. This information is increasingly relevant in modern society, where online shopping trends are growing while fake and misleading product reviews often run rampant.

Park joined the Moore School in August. This semester he will continue to work on research projects and will start teaching classes in the spring. He received his undergraduate degree in industrial engineering and applied statistics from Yonsei University and a master’s degree in industrial engineering from Seoul National University. He worked for the South Korean technology giant, LG Electronics, as a research engineer from 2010 to 2013, before coming to the United State’s to complete a doctorate degree in marketing at the Warrington College of Business from the University of Florida.

He has taught one marketing course previously at the University of Florida.

“I definitely prefer more interactive, of course,” Park said of his teaching style. “I ask some very mundane questions to the students. Why do retailers use 9-ending prices? Why do fast food chains provide bundled meal products? We observe this type of marketing tactics all the time in the real world, but it is not that easy to explain the reason and intuition behind this tactic.” he said.

These critical thinking skills are paramount in the modern corporate environment. In his classroom, Park hopes to create a discussion that challenges students to think a little harder. Next semester, he will be teaching marketing research.

“When you do research, you’re essentially writing the academic paper to be published. But, typically, an academic paper has a very narrow audience. In the classroom, a lot of students have a strong incentive to listen to what you’re talking about and give you feedback instantaneously,” Park said. “I think that’s the joy of teaching.”

Read Park’s more about “The Fateful First Consumer Review” here: http://www.msi.org/reports/the-fateful-first-consumer-review/

By Jenna Schiferl