Revealed: Amazon struggling to stem the tide of fake reviews

Retail giant Amazon is only removing a proportion of a flood of fake and suspicious reviews that risk misleading shoppers into buying poor quality products, a Which? investigation has found.

The consumer champion looked at the number of reviews that Amazon removes for popular tech products and found 78,000 that have been removed in the last three years.

When Which? looked at reviews for a single product category – headphones – on a single day, it found the vast majority of 12,000 reviews displayed on the first page of products were from unverified purchasers or had suspiciously high five-star ratings – two of the key red flags for fake reviews.

Furthermore, Which? found tens of thousands of potentially fake reviews on just a couple of dozen products, which suggests that far more needs to be done to truly address the problem.

According to data from ReviewMeta, the percentage of unverified reviews – meaning Amazon cannot confirm whether the reviewer has actually bought the product – has increased significantly. In the first quarter of 2018, six per cent of the reviews on Amazon were unverified, but for the same period in 2019 this had risen to 31 per cent.

In March 2019 the number of unverified reviews on Amazon rose by nearly 300 per cent compared to the previous month, with average star ratings of unverified reviews at 4.95 out of five.

Which? is warning that high numbers of unverified, positive product reviews could be an indication that a product’s overall rating is being manipulated by fake reviews.

Amazon told Which? that it estimates that more than 90 per cent of inauthentic reviews are computer generated. The company said it uses machine learning technology to analyse all incoming and existing reviews 24/7 and block or remove inauthentic reviews.

The problem of fake unverified reviews is compounded by evidence that unscrupulous businesses are finding ways to manipulate average product ratings with verified reviews.

Which? has exposed Amazon “review factory” Facebook groups, which encourage users of the social network to post positive reviews in return for payment of other incentives and further erode trust in the reliability of Amazon reviews.

Since Which? reported its findings to Amazon, many of the products or suspect reviews that it found in its recent this investigation have been removed. However, more products or suspicious reviews have immediately taken their place, suggesting that Amazon is struggling to stem the tide of fake reviews.

With 97 per cent of shoppers relying on online customer reviews to help make a purchase, fake reviews are a serious problem, which can mislead customers into buying products that are not fit for purpose.

The Competition and Markets Authority estimates that £23 billion a year of UK consumer spending is potentially influenced by online reviews and has warned that writing or commissioning fake reviews could lead to civil or criminal action.

Natalie Hitchins, Which? Head of Home Products and Services, said:

“Our research shows that while thousands of potentially fake reviews are being removed from Amazon each month, this isn’t nearly enough to address a real problem for online shoppers that seems to be getting worse, not better.

“To avoid being tricked into buying a product that you might otherwise have avoided, watch out for fake reviews and search for independent and trusted sources when looking to make a purchase.”

  • To find out more about expert testing and reviews from Which? and what makes a product a Best Buy, visit

Which? tips on how to spot a fake review

  • Take extra care shopping for brands you don’t know

Scrutinise customer reviews even more carefully if you’re looking to buy a brand you don’t recognise as our research indicates they are significantly more likely to be affected by fake reviews.

  • Be suspicious of large numbers of reviews

If you see hundreds or even thousands of reviews – be suspicious, especially if they are largely positive.

  • Look for repetition

If you see the same review titles, repetitive phrases or even the same reviewer name appear more than once on a product, it’s very likely that it has been targeted by fake reviews.

  • Filter to check for unverified versus verified reviews

Reviews marked as ‘verified’ are those that Amazon can confirm were purchased at its website. Unverified reviews do not undergo any such checks. Therefore, unverified reviews are far easier to ‘fake’ – in that they could be written by someone who has had no experience at all with the product.

  • Look at the dates

If large numbers of reviews were posted on the same day, or in a short period of time, it’s very likely that they are fake – especially if they are also unverified.

  • Check seller profiles

Things you might be wary of are foreign seller locations, strange business names, a lack of contact details, and of course, negative reviews of the seller. Check out the seller profile page before you buy to see if anything seems out of place.


  • In April, Which? looked at the number of reviews that Amazon has removed from its website since January 2016. The categories of products that Which? looked at were wireless speakers, headphones, smartwatches, fitness trackers, wireless security cameras, dash cams, compact cameras, action cams, radios, TVs, laptops, internet TV boxes, tablets, record players.
  • In a recent investigation Which? found thousands of potentially fake or suspicious reviews across popular tech and household products on Amazon.
  • Which? has found evidence that unscrupulous businesses are finding ways to manipulate average product ratings with verified reviews. In a follow up to its investigation into Amazon ‘review factories’ on Facebook, the consumer group found that four out of five Facebook groups were still facilitating the incentivised and paid-for Amazon reviews, raising more questions about how reliable customer reviews are – as highlighted in another recent investigation.
  • Review removal could indicate that product categories are being targeted by fake reviews to artificially inflate customer scores and rankings – potentially placing products with a lot of five star reviews higher up in search results when sorted by average customer score, or within Amazon’s featured reviews.
  • Online shopping analysts ReviewMeta analyses Amazon product reviews based on product page urls uploaded to its website by members of the public, this amounts to hundreds of thousands of reviews on each month. Although this does not equate to a perfectly random sample of products and reviews, neither is the sample steered by anything other than what members of the public have been researching on the website. Of the products analysed by ReviewMeta, six per cent were unverified in the first quarter of 2018, compared with 31 per cent in the first quarter of 2019.

Rights of reply

Amazon: The approach taken by Which? is flawed and its findings—based on research from an organisation that admits it can’t say whether any review is ‘fake’ and does not know how many reviews have been removed from Amazon—are inaccurate.

Amazon invests significant resources to protect the integrity of reviews in our store because we know customers value the insights and experiences shared by fellow shoppers. We have clear participation guidelines for both reviewers and selling partners and we suspend, ban, and take legal action on those who violate our policies.

We use a combination of teams of investigators and automated technology to prevent and detect inauthentic reviews at scale, and to take action against the bad actors behind the abuse. We estimate more than 90% of inauthentic reviews are computer generated, and we use machine learning technology to analyze all incoming and existing reviews 24/7 and block or remove inauthentic reviews. Our team investigates suspect reviews, works with social media sites to stop inauthentic reviews at the source, pursues legal action to stop offenders  from planning reviews abuse, and feeds new information into our automated systems so it continues to improve and become more effective in catching abuse.

We work hard to enrich the shopping experience for our customers [and selling partners] with authentic reviews written by real customers. Customers can help by reporting any requests they get to manipulate reviews to customer service.

Amazon’s statement on ReviewMeta: Amazon invests significant resources to protect the integrity of reviews in our store for our customers. We are able to assess review authenticity by looking at data points like reviewer, seller, or product history which  websites like ReviewMeta do not have access to and therefore cannot concretely determine the authenticity of a review. ReviewMeta itself admits that they do not have the data to know, or even say with high confidence, whether a review is fake which is why they use the term “Unnatural”. They consider reviews to be ”unnatural” if the customer has only ever submitted one review or if the customer did not purchase the product on Amazon or purchased it at a discount. We have data that disproves with high confidence many of their “unnatural” categorizations because we have the customer history behind each review.


Facebook: “We don’t allow people on Facebook to facilitate or encourage the trade of fake user reviews. The groups brought to our attention have now been removed for violating our policies. We urge people to continue to use our reporting tools to flag content they think break our rules so that we can investigate and take swift action”


Press Release: , , , , ,