Unscrupulous sellers are using a range of tactics to evade detection on Amazon and mislead shoppers with fake reviews, a Which? investigation has revealed.
After analysing thousands of reviews across hundreds of products, evidence emerged of exactly how Amazon sellers have found intricate ways to 'game' the system. We found:
Amazon product variation misuse
One seller tactic to boost positive reviews and remain undetected is product variation misuse. Legitimate sellers use variations to group different sizes of the same coat or different colours of the same mug under a single product ID or ASIN - Amazon Standard Identification Number, ultimately making your Amazon shopping a smoother experience.
But scammers have found a loophole, and are using the feature to create dozens, or in some cases hundreds, of spurious product variations, called things like 'Black1/Black2/Black3'. In one case we found five-star reviews from the same Amazon profile left across one hundred variations of a product. Sellers can do this in order to flood their products with fake reviews through Amazon's back door.
'If multiple people review the same product in a short space of time, that can flag a warning. A pop-up appears from Amazon saying you can no longer review the product,' said Prabhat Shah, from Online Seller UK, a Manchester-based Amazon Training provider.
Shah said that he believed sellers were creating spurious variations to get around Amazon's defences, adding: 'When you use different variations, each is using a different ASIN so Amazon won't flag a warning. It's wrong, but quite clever in a way.'
A pair of SDFLAYER headphones, which topped the headphones searching listings on 1 June, had 40 seemingly meaningless colour variations, and a steady stream of about 17 five-star reviews a day.
In another case, a Jumper laptop featured 49 spurious variations among its 65 reviews, all of them uploaded in a single day. Amazon removed the reviews without being prompted. But by 8 June, three new five-star reviews had appeared - all with equally bizarre variation names. Amazon has clearly woken up to the issue of fake reviews, but it feels a bit like a game of whack-a-mole when it comes to staying on top of the larger issue.
Variation abuse isn't the only way unscrupulous sellers are manipulating product ID codes to generate positive reviews.
We found examples of sellers merging dormant or unavailable products with new or existing product listings as a way to transfer positive reviews from one to another. Often the reviews will be for a completely different product - we've uncovered soap dispenser and phone screen cover reviews on headphones.In some cases the merged reviews will even have been dated before the product appears to have gone on sale.
We found a smartwatch with 938 reviews dating back to 2011, despite being first listed for sale in January 2019.
On 14 June, the same Jumper laptop referenced above accumulated around 200 additional reviews, most of which were from 2017. Amazon states that the date the laptop was first available was 3 June 2019, and it seems likely that these additional references were merged onto the product from another listing.
It's not uncommon for product listings of this type to end up with hundreds of reviews, making it difficult to spot rogue reviews without scrolling through multiple pages.
In response to the findings, Amazon said that any attempt to manipulate customer reviews is strictly prohibited, and that it invests significant resources to protect the integrity of its reviews.
In our , we went undercover and found Facebook Groups with tens of thousands of members. These groups are designed to generate incentivised positive reviews for Amazon product purchases. In a follow-up, we found that four of the five groups were still active - and had nearly 70,000 members. We contacted Facebook and it removed the four groups we flagged.
However, our most recent investigation revealed more than 70 similar groups. One had more than 22,000 members, while another two had more than 19,000 members each.
Facebook review groups are incredibly active places. In just one group we counted 133 new posts in an hour.
These groups generate 'verified purchase' reviews on Amazon on a potentially huge scale, which could lead you to think that the reviews are genuine. And if a group is shut down, another quickly pops up in its place. One review group anticipated the issue, alerting members to an alternative group in case of a shut down.
How effective are they at generating positive reviews? We checked six products found on these groups on Amazon and found that 92% of the customer reviews were five-star. The products had, on average, a customer score of 4.8 out of 5, and many of the customer reviews also included photos, a telltale sign of incentivised review groups.
On 21 June, the Competition and Markets Authority (CMA) urged both Facebook and eBay to act on the sale of fake reviews. Facebook informed the CMA that most of the 26 groups it reported had been removed, but we found dozens more since, based on associated search terms.
We contacted Facebook about the findings, and a spokesperson said: 'Fraudulent activity is not allowed on Facebook, including the trading of fake reviews, and we have removed all of the groups Which? reported to us. We know there is more to do to tackle this issue, which is why we've tripled the size of our safety and security team to 30,000 and continue to invest in technology to help proactively prevent this kind of abuse.'
We also found eBay listings from people 'selling' a five-star review - a service, effectively, where someone will write your product or company a glowing review for a price. These were offered for a range of platforms including Google, Tripadvisor, Trustpilot or in some cases 'any other platform you desire'.
Since the CMA reported these listings to eBay, it appears as though they have been successfully removed.
Disturbingly, we've heard from several Which? members who have had their Amazon accounts hacked, and reviews left on multiple products from their profile.
One member told us that their account was hacked overnight and 84 reviews were left in a matter of hours on cheap technology products, including headphones, and that their account was hacked again within hours of Amazon reinstating it.
One Which? reader told us that a fake reviewer hacked their profile and left 2,552 reviews across a variety of products.
In both cases, the victims had to remove the fake reviews themselves - a manual process.
In response to these issues, Amazon warned about the dangers of 'phishing' emails that may appear to come from Amazon but direct recipients to a false website where they might be asked to provide sensitive information. It advises all customers to go directly to Amazon before making any changes to their account.
Nearly three months after discovering, Which? searched the suspect categories again. Since we reported our findings to Amazon in April, this particular issue has dramatically improved - in fact comparatively few unverified reviews were found.
Our findings were corroborated by analysts ReviewMeta, who found that the number of unverified reviews posted on Amazon had gradually dropped from a high of 35% in March to just 5% in May.
This particular issue certainly seems to have been improved, but it hasn't been eradicated.
More than one in ten products we analysed had received ten or more reviews in a single day - a conservative threshold for suspicious activity when you consider that Samsung phones we analysed, which have hundreds more overall reviews than the products we're concerned about, never received more than seven reviews in a 24-hour period.
Some 11 products with between 0% and 50% verified reviews continued to find their way onto the first page of the Amazon.co.uk searches we carried out.
Interestingly, it seemed that products with a really low proportion of verified reviews skewed towards the top of the rankings. As this graph shows, there is a striking similarity between unverified reviews, products with multiple variations and review floods in this regard: those products with the most suspicious review history are making their way to the top of search pages.
This finding is a huge concern for consumers, and we strongly advise you to look beyond the products at the top handful of products when making a quick Amazon purchase. But it also begs the question: why isn't Amazon able to prevent products with suspicious review patterns climbing to the top of the results?
The problem with fake reviews isn't exclusive to the product categories we've looked at for our investigation.
We've been asking Which? readers to report their own experiences of fake reviews. To date we've received nearly 90 emails from people flagging fake reviews and sharing their own stories.
Get the latest: Amazon sorts 'top reviews' by default, so you won't see the most recent reviews first but the ones that have been voted as 'helpful' by other reviewers. Sort by 'recent reviews' instead.
Beware big numbers: If you see hundreds, or even thousands of reviews - be suspicious, especially if they are largely positive. If it's a brand you haven't heard of, or a relatively cheap product, then consider how likely it is that so many people would have left a review.
Be cautious of images: images of a product can be helpful, but we've found that incentivised review sellers usually request images in exchange for a refund. Consider how likely it would be for someone to include a range of images in a review if they weren't asked.
Watch out for variations: If product variations (shown under the review date) have obscure names or it seems unusual to see so many, be wary. It's unlikely that there are more than 10 variations of a pair of headphones, while multiple variations are fairly common for laptops, for example.
Data analysis and additional content by Josh Robbins and Paul Lester