Yelp More Likely To Filter Extreme Reviews & New Accounts [Study]

Yelp keeps the details of its review filter algorithm secret, for obvious reasons, but a new study suggests that there are some things about the review and the reviewer that are more likely to trigger the filter.

Michael Luca and Georgios Zervas recently published a working paper, Fake it Till You Make it: Reputation, Competition, and Yelp Review Fraud, that’s based on a study of more than 316,000 Yelp reviews of Boston restaurants. Their study covered more than 3,600 different businesses.

They found that Yelp’s review filter had hidden more than 50,000 of those, or about 16 percent of all the reviews they scraped for the study. And those filtered reviews shared some common characteristics tied both to the review itself, and to the person/account that wrote it.

1- & 5-Star Reviews Are Filtered More

The study found that the ratings of filtered Yelp reviews are more extreme than published reviews. As the chart below shows, the number of filtered 1-star and 5-star reviews is higher than the number of reviews published with those ratings.


Overall, with everything else being equal, 1- and 5-star reviews are about 3 percentage points more likely to be filtered than 3-star reviews.

The study also found that filtered reviews tend to be shorter than published reviews.

Reviewer Characteristics & Filtered Reviews

Beyond the reviews themselves, the study also connects the person/account writing the review to its likelihood for being filtered.

Filtered reviews tend to be more commonly written by accounts that haven’t posted a lot of reviews. In the study, more than 70% of accounts that had only written one review had that review filtered. Furthermore, the more reviews an account writes, the less likely that account is to have its reviews filtered.


One other interesting finding in the study: reviews from users that don’t have a profile image are 41 percentage points more likely to be filtered than accounts that have a profile image.

To a degree, the data confirm what reputation management best practices have suggested for some time now: Yelp reviews written from trusted accounts are more likely to “stick.” And this is why so many local businesses get frustrated when they first ask customers (or friends!) to write positive reviews on Yelp; if those people aren’t already known Yelp users with trusted accounts, their reviews — whether real or fake — are more likely to be filtered.

Speaking Of Fake Reviews…

The study also gets into the issue of fake reviews on Yelp, and draws a few conclusions that are worth mentioning briefly:

  • Restaurants are more likely to engage in review fraud when they have fewer reviews
  • Restaurants that have recently received bad reviews are more likely to engage in positive review fraud
  • Chain restaurants are less likely to leave fake reviews compared to independent restaurants
  • Businesses with claimed pages are significantly more likely to post fake 5-star reviews

That last point seems counterintuitive, perhaps, but the study notes that this aspect of the data — trying to determine what reviews are fake and which aren’t — is “imperfect” because Yelp admits that its review filter doesn’t catch all fake reviews, and not all filtered reviews are fake.

The full paper can be downloaded in PDF format.

Related Topics: Channel: Local | Features & Analysis | Top News | Word Of Mouth Marketing | Yelp


About The Author: is Editor-In-Chief of Marketing Land. His news career includes time spent in TV, radio, and print journalism. His web career continues to include a small number of SEO and social media consulting clients, as well as regular speaking engagements at marketing events around the U.S. He recently launched a site dedicated to Google Glass called Glass Almanac and also blogs at Small Business Search Marketing. Matt can be found on Twitter at @MattMcGee and/or on Google Plus. You can read Matt's disclosures on his personal blog.

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  • Review HELPER

    An extremely informative study, but with its focus on “fake” reviews, it does not address the issue of “solicitation” of reviews, which is of critical importance to honest business owners. The very same behaviors and reputation changes that correlate to business owners posting fake positive reviews also correlates to business owners being overly aggressive in soliciting real reviews from real customers. This is a problem because Yelp’s review filter does not discriminate between the two. It just sees the behaviors and filters reviews.

    Typically, the business owner gets a bad review, wants to vindicate the business, and so asks all his or her happy customers to speak up for the business. This results in a lot of 5-star reviews. Another factor not addressed in the study is the historical pattern of reviews submitted by a particular business, as well as the historical pattern of a particular business category in a particular market (Yelp acknowledges it looks at this). So these are “norms.” Yelp’s review filter sees deviations from the norms as a likely attempt to deceive. So if a business averages two submitted a reviews over the past two years, then suddenly receives 10 five-star reviews in a week because the owner posted a plea on the business’s Facebook page–well that business may get itself into deep trouble with Yelp’s review filter, from which it will be difficult to extricate itself.

    This is another factor not addressed in the study: the dynamic nature of Yelp’s filter. Because it is our business to help companies get honest reviews they deserve, we spend a great deal of time analyzing specific situations. We work with clients on these issues in real time. It seems to us that Yelp’s filter becomes harsher on a business after it detects what it believes is deception. It may sweep back in time and remove positive reviews, and make it more difficult to get them published for a period of time moving forward.

    We’re also strongly convinced that Yelp’s filter has different standards for different industries, i.e., it is stricter on the more competitive industries. We provide real examples for the points made in this post on our Yelp reviews FAQs page.

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