Book excerpt: Manipulating customer reviews

(This is an excerpt from my book, "Algorithms and Misinformation: Why Wisdom of the Crowds Failed the Internet and How to Fix It")

Amazon is the place people shop online. Over 40% of all US e-commerce spending was on Amazon.com in recent years.

Amazon also is the place for retailers to list their products for sale. Roughly 25% of all US e-commerce spending recently was third-party marketplace sellers using the Amazon.com website to sell their goods. Amazon is the place for merchants wanting to be seen by customers.

Because the stakes are so high, sellers have a strong incentive to have positive reviews of their products. Customers not only look at the reviews before buying, but also filter what they search for based on the reviews.

“Reviews are meant to be an indicator of quality to consumers," Zoe Schiffer wrote for The Verge, “[And] they also signal to algorithms whose products should rise to the top.”

For example, when a customer searches on Amazon for [headphones], there are tens of thousands of results. Most customers will only look at the first few of those results. The difference between being one of the top results for that search for headphones and being many clicks down the list can make or break a small manufacturer.

As Wired put it in an article titled “How Amazon’s Algorithms Curated a Dystopian Bookstore”: “Amazon shapes many of our consumption habits. It influences what millions of people buy, watch, read, and listen to each day. It’s the internet’s de facto product search engine — and because of the hundreds of millions of dollars that flow through the site daily, the incentive to game that search engine is high. Making it to the first page of results for a given product can be incredibly lucrative.”

But there is a problem. “Many curation algorithms can be gamed in predictable ways, particularly when popularity is a key input. On Amazon, this often takes the form of dubious accounts coordinating.”

The coordination of accounts often takes the form of paying people to write positive reviews whether they have used the item or not. It is not hard to recruit people to write a bogus positive review. A small payment and being allowed to keep the product for free is usually enough. There are even special discussion forums where people wait to be offered the chance to post a false positive review, ready and available recruits for the scam.

BuzzFeed described the process in detail in an investigative piece, “Inside Amazon’s Fake Review Economy.” They discuss “a complicated web of subreddits, invite-only Slack channels, private Discord servers, and closed Facebook groups.” They went on to detail how “sellers typically pay between $4 to $5 per review, plus a refund of the product ... [and] reviewers get to keep the item for free.”

Why do merchants selling on Amazon do this? As Nicole Nguyen explained in that BuzzFeed article, “Being a five-star product is crucial to selling inventory at scale in Amazon’s intensely competitive marketplace — so crucial that merchants are willing to pay thousands of people to review their products positively.”

Only one product can appear at the top of an Amazon search for [headphones]. And the top result will be the one most customers see and buy. It is winner take all.

“Reviews are a buyer’s best chance to navigate this dizzyingly crowded market and a seller’s chance to stand out from the crowd ... Online customer reviews are the second most trusted source of product information, behind recommendations from family and friends ... The best way to make it on Amazon is with positive reviews, and the best way to get positive reviews is to buy them.”

Because so few customers leave reviews, and even fewer leave positive reviews, letting the natural process take its course means losing to another less scrupulous merchant who is willing to buy as many positive reviews as they need. The stakes are high, and those who refuse to manipulate the reviews usually lose.

“Sellers trying to play by the rules are struggling to stay afloat amid a sea of fraudulent reviews,” Nguyen wrote. It is “really hard to launch a product without them.”

More recently, Facebook Groups have grown in popularity, generally and as a way to recruit people to write fake reviews. UCLA researchers described in detail how it works, finding “23 [new] fake review related groups every day. These groups are large and quite active, with each having about 16,000 members on average, and 568 fake review requests posted per day per group. Within these Facebook groups, sellers can obtain a five-star review that looks organic.” They found the cost of buying a fake review to be quite cheap, “the cost of the product itself,” because “the vast majority of sellers buying fake reviews compensate the reviewer by refunding the cost of the product via a PayPal transaction after the five-star review has been posted” with only a small number of the bad sellers also offering money in addition to a refund of the cost of the product.

Washington Post reporters also found “fraudulent reviews [often] originate on Facebook, where sellers seek shoppers on dozens of networks, including Amazon Review Club and Amazon Reviewers Group, to give glowing feedback in exchange for money or other compensation.”

You might think that getting caught manipulating reviews, and through fake reviews also getting featured in search and in recommendations, might have some cost for sellers if they were to get caught. However, Brad Stone in Amazon Unbound found that “sellers [that] adopted deceitful tactics, like paying for reviews on the Amazon website” faced almost no penalties. “If they got caught and their accounts were shut down, they simply opened new ones.”

Manipulating reviews, search rankings, and recommendations hurts Amazon customers and, eventually, will undermine trust in Amazon. While Amazon reviews have been viewed as a useful and trusted way to figure out what to buy on Amazon, fake reviews threaten to undermine that trust.

“It’s easy to manipulate ratings or recommendation engines, to create networks of sockpuppets with the goal of subtly shaping opinions, preying on proximity bias and confirmation bias,” wrote Stanford Internet Observatory’s Renee DiResta. Sockpuppets are fake accounts pretending to be real people. When bad actors create many sockpuppets, they can use those fake accounts to feign popularity and dominate conversations. “Intentional, deliberate, and brazen market manipulation, carried out by bad actors gaming the system for profit ... can have a profound negative impact.”

The bad guys manipulate ranking algorithms through a combination of fake reviews and coordinated activity between accounts. A group of people, all working together to manipulate the reviews, can change what algorithms like the search ranker or the recommendation engine think are popular. Wisdom of the crowd algorithms, including reviews, require all the votes to be independent, and coordinated shilling breaks that assumption.

Nowadays, Amazon seems to be saturated with fake reviews. The Washington Post found that “for some popular product categories, such as Bluetooth headphones and speakers, the vast majority of reviews appear to violate Amazon’s prohibition on paid reviews.”

This hurts both Amazon customers and other merchants trying to sell on Amazon. “Sellers say the flood of inauthentic reviews makes it harder for them to compete legitimately and can crush profits.” Added one retailer interviewed by the Washington Post, “These days it is very hard to sell anything on Amazon if you play fairly.”

Of course, this also means the reviews no longer indicate good products. Items with almost entirely 5 star reviews may be an “inferior or downright faulty products.” Customers are “left in the dark” using “seemingly genuine reviews” but end up buying “products of shoddy quality.” As Buzzfeed warned, “These reviews can significantly undermine the trust that consumers and the vast majority of sellers and manufacturers place in Amazon, which in turn tarnishes Amazon’s brand.”

Long-term harm to customer trust could eventually lead people to shop on Amazon less. Customer Reports, in an article titled “Hijacked Reviews on Amazon Can Trick Shoppers,” went as far as to warn against using the average review score at all: “Fraudulent reviews are a well-known pitfall for shoppers on Amazon ... never rely on just looking at the number of reviews and the average score ... look at not only good reviews, but also the bad reviews.”

Unfortunately, Amazon executives may have to see growth and sales problems, due to lack of customer trust in the reviews, before they are willing to put policies in place to change the incentives for sellers. For now, as Consumer Reports said, Amazon's customer reviews can no longer be trusted.