Amazon’s battle with ‘unbiased’ product reviews

Amazon’s battle with ‘unbiased’ product reviews

Many star ratings artificially high because reviewers are given products for free, study finds.

Sarah Coles

Household money

Sarah Coles
Updated on 20 September 2016

The star ratings of many products on Amazon are being artificially boosted by incentivised reviews, new research has revealed.

While it’s not uncommon – or illegal – for people to be given goods in return for writing a review, Amazon’s guidelines require that they are explicit about this fact in their review.

This makes it easier for Amazon shoppers to distinguish between a traditional customer review and an incentivised one.

The problem, according to product review platform ReviewMeta, is that the star ratings on Amazon are all bundled together.

Its data found incentivised reviewers were 12 times less likely to give a one-star review and rated products on average 0.38 stars higher.

While that might not seem much of a difference, it could actually prove hugely significant, says ReviewMeta.

“The average product on Amazon is rated around 4.4 stars, so a boost from 4.36 to 4.74 stars can mean the difference between a mediocre product and a top-rated product.”

The company added that the number of incentivised reviews on Amazon was on the rise, and actually outnumbered “traditional” reviews over the past six months.

Indeed, a quick scan of Amazon's pages shows numerous products where the only reviews you’ll find are from people who either received that item for free or at a discount.

While the vast majority of reviewers are clear how they obtained the goods, the research from ReviewMeta does suggest many people struggle to offer a truly unbiased review for an item that they haven’t paid full price for.

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Amazon reviews

What is Amazon doing about it?

When we spoke to Amazon earlier this year about it's problem with incentivised and outright fake reviews, a spokesperson told us: “We use a number of mechanisms to detect and remove the small fraction of reviews that violate our guidelines, and we terminate accounts.”

It’s definitely not taking the situation lying down. In the past year it has filed three lawsuits, targeting more than 1,000 reviewers, and used information gleaned from this action to shut down thousands of accounts offering fake reviews.

Earlier this year, it announced it was taking another five websites to court for offering retailers the chance to buy fake Amazon reviews.

The spokesperson said: “We've recently filed lawsuits against a number of individuals and businesses who were abusing the system.”

However, it’s a continuous battle, because when one site is closed down, another one will spring up.

Does Amazon allow paid reviews?

The matter is arguably not helped by Amazon’s somewhat contradictory terms and conditions. It states:

“We do not permit reviews or votes on the helpfulness of reviews that are posted in exchange for compensation of any kind, including payment (whether in the form of money or gift certificates), bonus content, entry to a contest or sweepstakes, discounts on future purchases, extra product, or other gifts.”

But crucially, it then adds:

“The sole exception to this rule is when a free or discounted copy of a physical product is provided to a customer up front. In this case, if you offer a free or discounted product in exchange for a review, you must clearly state that you welcome both positive and negative feedback.

“If you receive a free or discounted product in exchange for your review, you must clearly and conspicuously disclose that fact.”

So the terms state reviewers can’t receive compensation of any kind, but at the same time allows them to get discounted – or even free – goods purely in return for doing reviewing them.

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How to spot a biased or fake review

Of course, the problem of dodgy reviews is by no means limited to Amazon. 

There are a number of companies offering freebies in return for posting product reviews, and all online retailers have their work cut out trying to clampdown on this growing industry.

The problem is there’s an almost endless stream of people willing to spend a few minutes writing a review in return for a whopping great discount off the price of an item.

So while retailers do what they can, we also need to be able to protect ourselves by understanding how to spot the biased or fake reviews.

Here are a few warning signs.

Matt Eames, CCO of review platform Feefo, also suggests you consider emotion: “Check if the reviewer talks about the impact of the product or service on their lives. If it only talks about features without any emotion, chances are it’s a fake.”

Another warning sign is someone being overly positive or negative. Fake reviewers tend to go overboard, and indulge in superlatives, so they will point out that it’s not just a great product – it’s the best one they have ever tried.

In many cases, people receiving the freebies have posted the review after just looking at the product, or using it for a few minutes, which fulfills their part of the bargain, but provides no meaningful information. 

If you have the time and the patience, you can dig a little deeper to see whether you should trust a reviewer. Check their history. Do they only tend to share their opinion on products from a few companies? Do they always offer five star write-ups? These are both warning signs.

Eames also suggests looking at the different comments of a single individual. He says: “Check their language and tone. Multiple reviews that all sound similar could be a sign of fakery.”

You should also check the policy of the website. Some platforms, such as Feefo, will only allow people who have bought the product to leave a comment.

Others will identify users who have bought the item from the site. Amazon, for example, will show a ‘verified purchase’ logo by a review. Both should add weight to the writer’s opinion.


If you don’t have the time for this, one option is to rule out the overly positive five-star reviews and the overly negative one-star ones, and focus on those in the middle.

These will tend to have a more balanced view of the pros and cons, and no particular incentive to be too extreme.

You can also take a clever new shortcut, by using a fake review spotter.

These will quickly check through the write-ups for an item, and the history of each of the reviewers, to assess whether you can trust an overall rating. One that’s worth trying is

We used it to analyse a pair of Betron B750s earphones, which were on sale for £11.99 and came with thousands of glowing write-ups.

Fakespot worked out that these were genuine reviews pair of good headphones – and tracked down four representative and trustworthy comments, revealing that overall buyers thought they were very good for the price.

You might think you have no need for a service like this – and that you’d be able to spot a fake review a mile off. However, a study by Cornell University a few years ago, revealed that people are shockingly bad at this.

When asked to identify the fakes amidst a number of reviews, their success rate was equal to using a coin toss. So unless you take some precautions, you never know who you’re taking advice from.

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