Hunger Games: What’s Behind Yelp’s Fake Reviews?

| November 8, 2013 | 2 Comments
  • 2 Comments
A new study finds restaurants that face close regional competition are more likely to post fake positive reviews for themselves and negative reviews for competitors. Photo: Jeremy Brooks/Flickr

A new study finds restaurants that face close regional competition are more likely to post fake positive reviews for themselves and negative reviews for competitors. Photo: Jeremy Brooks/Flickr

Post by Serri Graslie, The Salt at NPR Food (11/8/13)

When it comes to scouting out a new bakery, pizzeria or noodle shop, there are few review sites that compare to Yelp. In turn, the reviews left on sites like Yelp can have a big effect on many restaurants’ bottom lines.

That’s created a huge incentive for businesses to write fake positive reviews about themselves, called “astroturfing.” Some fake reviews are written by the businesses, while others are produced in bulk by reputation management companies. Michael Luca of the Harvard Business School and Georgios Zervas of Boston University wanted to figure out the exact conditions under which companies have strongest incentive to leave a fake review.

Luca and Zervas analyzed 316,415 reviews for 3,625 Boston-area restaurants written between 2004 through 2012, all of which Yelp had already flagged as potentially fraudulent. These “filtered” reviews make up about 25 percent of the 42 million total reviews submitted for all businesses. Of the filtered reviews, Luca and Zervas found 16 percent of reviews weren’t legitimate.

But defining fraudulence is tricky, especially since Luca and Zervas don’t know exactly what makes Yelp’s private algorithm tick. According to guidelines from the Federal Trade Commission, a review written by the business owner, family members, competitors or a compensated reviewer would be considered false advertising. But an owner who encourages users to review his restaurant (and provides instructions) falls into a grey area.

Luca and Zervas’ study, which is currently being reviewed by a journal for publication, draws a few large conclusions about who cheats and why. They found that restaurants that have a “weak” reputation (few and/or poor reviews) are more likely to boost their presence with fake positive reviews. Those that faced more regional competition might write positive reviews for themselves and leave negative reviews for competitors. Luca and Zervas also found that chain restaurants, which do not benefit greatly from Yelp, are less likely to commit review fraud.

Luca says he was surprised to find that ethics had nothing to do with it.

“This type of decision was influenced by the amount of competition and incentives,” he says. “This wasn’t just a story of a few rotten apples that were going to leave a bad review no matter what.”

The number of posts Yelp has to filter has increased dramatically in its nine-year existence. Luca says its part of an “arms race” between the review sites and scammers.

“People are finding increasing sophisticated ways to get around the algorithms,” he says. And, as Zervas told Boston University, as more consumers make decisions with on crowd-sourced reviews, businesses have a higher incentive to cheat.

But those developing the algorithms are also creating new tools that might make fake reviews less relevant in the first place. Luca’s next project is working with health inspectors to tap into a restaurant’s reviews and predict which ones might have hygiene violations.

If a restaurant’s Yelp page is branded with a “pest infestation” alert, it might be hard to distract with the fake review: “Great nachos, fast service.”

Copyright 2013 NPR.

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Food and Health-related stories from NPR including NPR Radio; NPR's food blog, "The Salt"; NPR's Health News blog, "Shots"; NPR's Breaking News blog "The Two-Way"; NPR's economy explainer "Planet Money"; food-related technology news from NPR's "All Tech Considered"; and food series "Kitchen Window."
  • Jen Shanks

    What concerns me about this post is the suggestion that only fake positive reviews occur – making restaurant owners sound like the only example of Yelp cheats. Hopefully Luca and Zervas (the study authors) and NPR will apply an equitably objective look at false negative reviews, which happen on a too frequent basis (although probably not with the same rate of occurrence or enterprise behind it). But, when it does happen, it can significantly damage a rating – yet restaurateurs have almost zero recourse or control via Yelp.

  • sanoran_t

    Jeremy Stoppleman, Yelp founder, raped a 14 year old girl Jewish girl
    and sodomized her, according to a review I just read. According to this
    review (which i know is authentic) Jeremy Stoppleman is a child molester
    and sex-offender, and has managed to evade the law because the Jewish
    girl was an orphan and no one was there to fight for her.

    I also heard that someone has offered to hide this review if Jeremy Stoppleman paid him $850/month.

    Looks like someone is using Jeremy Stoppleman’s business model against him.