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Review websites try to thwart false customer ratings

Seventy times a minute, 4,000 times an hour, new content is submitted to TripAdvisor. And for every hotel or restaurant review that pops up, an intense fraud detection effort kicks in.

Suspicious reviews flagged by automated software are sent to dozens of former law enforcement officers, identity theft experts, and credit card fraud specialists in six countries who try to determine whether the review is legitimate, or a business’s manufactured attempt to win customers.

Such detective work is part of the escalating battle being waged by review sites such as TripAdvisor and Yelp as they try to protect their credibility in an age of pervasive fake reviews. Researchers estimate that up to one-third of online reviews are phony — many on small sites without robust fraud detection.


“We have some of the brightest minds in Silicon Valley working on this,” said Darnell Holloway, manager of local business outreach for San Francisco-based Yelp. “It is an ongoing cat and mouse game.”

And when companies are caught, regulators are cracking down. In New York, 19 companies agreed to pay $350,000 in penalties for manipulating and fabricating online reviews, Attorney General Eric T. Schneiderman said this week.

As the number of online reviews soars, sites are adopting more sophisticated methods to root out fraud. Companies are tight-lipped about specific techniques because they don’t want to tip off those trying to game the system.

But the stakes are high: Restaurants that elevate their Yelp ranking by one star see revenues rise by 5 to 9 percent, according to a 2011 Harvard Business School study. Meanwhile, consumers are increasingly skeptical of the authenticity of online reviews, which could threaten a “credibility crisis” that renders review sites obsolete.

A survey released last week by marketing research firm Maritz Research found that 1 in 4 people believe customer ratings are biased or fake.


Alison Smith of Wrentham usually reads reviews before she buys a new toy for her 2-year-old son, and always takes them with a grain of salt. But after learning that a third of online reviews could be fake, her skepticism has grown.

“Any time from this point forward that I read one,” she said, “I’ll probably be thinking, is this real?”

Newton-based TripAdvisor has screened submissions since Stephen Kaufer started the company in 2000 to let travelers provide real, unvarnished reviews of hotels and tourist attractions — the good, the bad, and the ugly balcony views. With more than 100 million reviews on its site today, the company is relentless in its authentication efforts, constantly tweaking algorithms and advancing detection methods to stay a step ahead.

Before visitors even submit a word, TripAdvisor tracks their actions. Each review is scored by software scanning for 50 to 70 signals of potential irregularities, such as a large number of people writing reviews for the same hotels.

At TripAdvisor, investigators comb postings for abnormal patterns: Are multiple reviews for one hotel coming from the same IP address, or the hotel’s IP address? Do several reviews contain identical typos? Does the reviewer continually express opinions that are wildly inconsistent with the majority?

Even specific words can raise suspicions. Cornell University researchers developed software that accurately identified phony reviews using linguistic cues; real hotel guests used concrete descriptions like “bathroom,” for example, whereas deceitful posts were more likely to include scene-setting phrases like “vacation” or “my husband.”


When TripAdvisor identifies suspicious activity and a business owner doesn’t take action, a “big red badge of shame” goes up on the page.

“There’s nothing more important than the integrity of our content,” said Adam Medros, vice president of global product for TripAdvisor. That said, he noted: “I couldn’t look you in the eye and tell you we catch everything.”

Some sites pose as reputation management firms peddling positive online reviews or hotel owners looking to buy them. Yelp has sued several companies over false reviews and, during sting operations, has caught everything from a pest control company offering $5 to anyone willing to post a review written by the company to a jewelry store promising $200 for a positive write-up of a custom-designed ring.

The review site filters out about a quarter of its 42 million reviews, some considered fake, others just unhelpful.

Despite all these efforts, some sham reviews get through. A user on the website Fiverr, where people offer to perform tasks for $5, claims to have a team of people who have been writing fake reviews for a year, using an “SEO trick” to escape detection. “I will ensure you a believable, positive review and will post it as though I am a patron of yours,” wrote Raman2572. “No one will know! I will do all necessary research!”

Of course, cracking down too harshly is also problematic. Ziggy Hussain, owner of an Indian restaurant in England, threatened to take legal action against TripAdvisor after the company removed hundreds of positive reviews it deemed suspicious and temporarily knocked down the popularity rating of his restaurant.


Hussain says the reviews were real, written by satisfied customers whom he encouraged to post reviews. TripAdvisor maintains that the removals were justified.

Christos Faloutsos, a computer science professor at Carnegie Mellon University in Pittsburgh, said some companies he has consulted with about fraud have decided it isn’t worth it to monitor their customers too closely. “Eventually they figured out it was better to let fraud happen and absorb the fraud cost than annoying honest customers,” he said.

Some businesses just want TripAdvisor to admit they can’t catch everyone. After several establishments complained to the London-based Advertising Standards Authority, the advertising watchdog ruled last year that TripAdvisor can no longer use phrases such as “trusted advice from real travelers” in advertisements on its UK site.

The majority of online reviews are positive, but several analysts note that the number of negative fake reviews aimed at competitors is on the rise. Unfavorable ones are more likely to escape detection, according to the British online reputation management company KwikChex, because fraud detection systems are geared toward fake positive reviews.

The growing number of reviews posted from smartphones is also a weak spot because their mobility makes them harder to track, said Chris Emmins, cofounder of KwikChex, which has helped several businesses protest TripAdvisor’s fraud detection policies.

“With just a modicum of knowledge and easily available apps,” he said, “the systems can be circumvented quite easily.”


Katie Johnston can be reached at Follow her on Twitter @ktkjohnston.