Highly rated tech products sold on Amazon, including those recommended as 'Amazon's Choice', have been rated as Don't Buys in Which? labs, in an investigation into fake reviews and the reliability of Amazon's customer scores.
The chosen products all included telltale signs of suspicious or fake review activity. Five of the eight products were also labelled 'Amazon's Choice', with an average rating of at least 4.3 stars out of 5 from what were often hundreds of Amazon customer reviews.
All were offered by Chinese sellers, the majority of which were based in Shenzhen, and many were from brands that were all but unknown online outside marketplace stores. But after rigorous testing, none of them lived up to expectations.
The worst products on test included:
We got hands-on with the Onson wireless vac to see whether it's really worth all those 5-star reviews.
Over the past year, Which? has been highlighting the problems fake reviews cause for consumers, and how they muddy the waters of an increasingly competitive online shopping experience by artificially inflating the scores of inferior products.
Fake reviews are difficult to spot. In some cases you might think it's just possible that an unusually large number of people reviewed and loved a product.
To investigate further, we ran a selection of tech through the full gamut of Which? lab tests. The Amazon pages of the chosen products contained what our experts determined to be typically suspicious or fake review activity. Three products were so bad that we labelled them Don't Buys.
A cordless vacuum cleaner for less than £110 that gets an average customer rating of 4.6 stars? If it seems too good to be true, then it often is. Despite the cheap price and positive Amazon reviews calling this model 'Great!' and 'Brilliant!', our experts were far from impressed when putting this vacuum to the test.
As shown in the video further up the page, it's difficult to use and unhygienic to empty. It scored just one star for cleaning on carpets, floorboards and laminate flooring, and was also poor at removing pet hair.
One reviewer claimed that 'the company give cash rewards (via a scratchcard in the box) in return for 5 star reviews'. We purchased this vacuum cleaner ourselves, and also received a scratchcard, which offered a 'prize' of £5. To get the prize, we were told to write a review for the product, and send proof to receive the reward. This is against Amazon's policies. Amazon states that 'any attempt to manipulate customer reviews is strictly prohibited'.
In addition, more than 40% of the Onson cordless vacuum reviews included images or videos, something we know is requested by sellers on Facebook review groups, who then refund the cost of the product in return for a positive review. Every single one of the reviews that included photos or video gave five stars.
After we reported this vacuum cleaner to Amazon on suspicion of fake reviews, the product was made 'currently unavailable'.
An overall rating of 4.3 out of 5, from more than 800 reviews, might make you think these cheap noise-cancelling Amazon's Choice headphones are a bargain. 'Powerhouse sound' and 'great quality' were among the positive comments, but our experts wholeheartedly disagreed.
We described the sound as 'exceptionally poor', and said 'these in-ear headphones have such poor sound the passable noise cancelling is worthless'. Despite a number of five-star reviews lauding the impressive bass, we thought the sound was tinny and thin, with a lack of depth.
The number of reviews for the Yineme headphones dropped from a lofty 1,160 to just 45 between 10 and 26 September, suggesting Amazon took action against the suspicious-looking reviews. Based on 45 reviews, the average customer rating also dropped to 3.6 out of 5 - a correction that shows how easy it is to be duped into buying products that are better than they might appear on the online marketplace.
Shortly after we reported these headphones to Amazon on suspicion of fake reviews, the product was made unavailable.
With a near perfect 4.9-star customer review score on Amazon from hundreds of reviews - 86% of which were five-star - you might think you'd be in for a treat with these £45 wireless headphones.
But we found that the sound quality is unforgivably poor. The battery lasted for a little more than three hours, well below average, despite one Amazon customer review claiming 'Superb battery life'.
Another red flag on Amazon Marketplace listings are review surges, or high numbers of reviews being left in a short space of time. The number of reviews on these headphones has nearly trebled in three months, to over 1,000. Since the start of September, they received an average of 6.8 five-star reviews each day, and there were 14 five-star reviews on 12 October alone.
By comparison, the popular Apple AirPods received an average of just 1.2 five-star reviews each day.
Not all of the products we tested performed poorly enough to earn Don't Buys, despite similar signs of suspicious review activity. That said, none truly impressed our experts.
At the time of sending the Chortau dash cam for testing, it had 558 reviews with an average customer score of 4.5 stars out of five, with many reviewers saying it is easy to fit or an 'excellent product'. The story was different in our labs. While it's not a Don't Buy, the footage from this dash cam is only mediocre and it could be much easier to fit and demount.
So why is it reviewed so positively on Amazon? We found multiple reviewers clearly stating that the product came with an offer for a free micro-SD card in return for a favourable review, with some citing that the number of positive reviews could well be fake as a result.
It was a similar story with the ZoeeTree S1 Bluetooth Speaker, which achieved 4.3 stars on Amazon from a massive 1,677 reviews. A number of reviewers claim they were incentivised to delete or change critical reviews, with one stating they were offered a '100% refund if I change the review to 5 stars or remove it completely'. It performed reasonably in our tests, scoring 57%, but ultimately couldn't live up to its high customer score (and 'Amazon's Choice' status).
The results of our investigation show that when shopping on Amazon for what might appear to be well-reviewed, cheap products, it's a bit of a lottery. The rise of fake reviews means consumers face a confusing and potentially misleading proposition when relying on customer scores, and has led to an extremely challenging environment for small businesses legitimately trying to raise interest in their products.
We believe fake reviews are being used routinely by unscrupulous online sellers to undermine the honest small businesses legitimately using online marketplaces to reach new audiences.
We are concerned that Amazon is failing to take strong action to stop these fake reviews, which are continuing to dupe millions of its customers, and that online retail firms must be more responsible for the information presented to consumers on their platforms.
These findings provide yet further evidence that the Competition and Markets Authority should ensure the scope of its ongoing investigation into fake and misleading reviews includes online sites that allow user reviews, so that online customer reviews are less of a minefield for consumers using genuine customer feedback to decide what products to buy.
Natalie Hitchins, Which? head of home products and services, said: 'Customer reviews should be a helpful resource for shoppers choosing what to buy, and billions of pounds are spent every year based on this feedback, so it's vital that Amazon takes stronger action to ensure people can trust the information they see online and aren't duped into buying poor-quality products.
'There appears to be no sense of urgency from the industry to tackle this problem, so it's down to the regulator to make that happen. We urge the regulator to investigate how fake reviews are used to manipulate consumers, and to crack down on sites that fail to take appropriate action to combat this.'
When we emailed Amazon with our findings, it reiterated its stance on fake reviews. It claimed that it is relentless in its efforts to protect review integrity, and that in the past month over 99% of the reviews read by customers were authentic. It also said that last year its team of investigators prevented more than 13 million attempts to leave an inauthentic review, and took action against more than five million bad actors.
Our most recent investigation shows that more needs to be done to prevent review abuse from affecting online marketplaces, both for the benefit of consumers looking to make an informed purchase and legitimate small businesses selling their products.
And if you've come across online customer reviews you think are suspicious and may be fake, or have been approached to write an incentivised positive review for a product, you can help by sharing your experience. Get in touch and tell us your story - email the Which? Fake Reviews team at .