You shouldn’t believe everything you read. And if you’re reading online reviews of products, hotels, restaurants, or local businesses or services? Then you should believe even less.
It’s obviously in the best interests of a business to boost its online ratings. Good reviews and top ratings draw in customers, and also help businesses land higher results in online searches. Online reviews are so important that businesses have been known to plant reviews by employees, pay strangers who have never been customers to write five-star reviews, and even sabotage their competitors by the posting of harsh, negative reviews.
At the same time, it’s obviously in the interests of sites that host reviews and ratings—Yelp, Amazon, TripAdvisor, RateMDs, and so on—to root out the frauds, and maintain a semblance of trust with their users. By most accounts, these sites try their best. Yelp actually has a reputation for aggressively filtering out all sorts of suspicious reviews; its algorithms successfully flagged the vast majority of fake reviews planted at the site during one experiment last year.
Even so, there are plenty of reasons why it’s unwise to accept online reviews at face value and think you’re getting the 100% honest truth. Such as:
The marketplace for fake reviews operates fairly openly. Sites such as Freelancer.com welcome businesses to offer menial-paying jobs for writing fake reviews, and there are plenty of fake review writers offering their services at Fiverr.com, usually to the tune of $5 for each glowingly positive review.
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Companies give freebies in exchange for reviews. A New York Times story reported that a company called VIP Deals had been reimbursing customers for their tablet case purchases if they posted a review of the product on Amazon. And wouldn’t you know? At one point, 310 out of the 335 product’s reviews received five stars.
Even if you think you can spot fake reviews, you probably can’t. Cornell researchers created software to detect “opinion spam” (fake online reviews) in a pool of 800 reviews—half fake, half real. While the software’s algorithms spotted the fakes 90% of the time, regular people doing the same were about as accurate as if they flipped a coin. To boost your chances of picking out the frauds, check out Consumerist’s list of 30 ways to spot fake online reviews.
One restaurant got a negative review before it even opened. It happened in 2010 to Grahamwich, a sandwich shop in Chicago owned by Graham Elliot, who has been a judge on the Fox show MasterChef. Apparently, someone read about the restaurant, skipped the part about it not actually being open for business yet, got mad after showing up and seeing it was closed, and then gave the place a one-star review on Yelp. Grahamwich now averages a three-star rating on Yelp.
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About 30% of online reviews for certain products are fake. That estimate comes from Bing Liu, a University of Illinois at Chicago computer science professor who has been working on software to out fake reviews (courtesy of Businessweek).
About 10% of other reviews are fake. That estimate comes from a team of Cornell researchers investigating online reviews and “opinion spam.” They created a website, Review Skeptic, where you can plug in a hotel review to see if their software thinks it’s fake.
The review could be from a real person—who works for the company being reviewed. A Wall Street Journal post chronicled an interesting situation in which a blogger searching for an espresso maker discovered that an Amazon customer named “T. Carpenter” had written 12 reviews on the site—all for products made by DeLonghi, where the reviewer happened to work. And needless to say: all five-star reviews.
Many doctors and dentists ban patients from posting reviews of their services. Patients often unknowingly sign an agreement prohibiting them from writing an online review of their doctor or dentist. After posting reviews of his dentist on Yelp and DoctorBase, one man received a letter threatening to sue him for at least $100,000 for defamation, slander, and libel—all for offering his opinion online. One site specialized in doctor ratings has created Wall of Shame page for doctors who make patients sign such “gag contracts.”
TripAdvisor removed the “trust.” Last fall, amid an investigation over allegations that millions of Trip Advisor reviews may be fake, the site decided to replace “Reviews you can trust,” the slogan for its online review section, with a new one: “Reviews from our community.”
Brad Tuttle is a reporter at TIME. Find him on Twitter at @bradrtuttle. You can also continue the discussion on TIME’s Facebook page and on Twitter at @TIME.