Amazon reviews: Loved, but also to be trusted?

Amazon has been successful in leveraging users to review its products … now, the integrity of those reviews are at stake.

Amazon has been incredibly successful in leveraging crowds – in the form of its own customers – to review products sold through The reviews create value for both sides in the marketplace. Customers can rely on reviews to research a product before buying, filter purchase options with minimum rating levels. Sellers benefit from a free marketing boost if obtaining many positive reviews and also get direct feedback from customers on how they perceive the product. Finally, Amazon itself captures value by providing an easy way for customers to evaluate purchases on its platform and by boosting traffic to well-performing sellers (which helps minimize customer complaints).

So, 5-star products are all good – right? Not necessarily!

Sellers have high incentives to manipulate their reviews, either to boost ratings of their own product or to drag down competitor ratings. Amazon has even seen politically motivated review-manipulation. Just a few hours after Hillary Clinton’s book “What Happened” had been released, the book quickly received 1,660 reviews which were either 1 or 5-star ratings. Amazon later found these to be fake and removed them [1]. Other fake reviews are more innocent of nature (I in particular like the banana slicer review below).

Banana slicer review

Up until October 2016, Amazon allowed sellers to provide discounts to customer in exchange for customer reviews. ReviewMeta [2] found that this policy significantly boosted the weight of incentivized reviews to make out the majority of ratings – and tended to be a lot more favorable. In October 2016, Amazon banned these reviews [3]. Today, however, review integrity still remains an issue – according to (a site the analyzes suspicious reviews on Amazon) 40% of reviews are unreliable* [4].

Amazon reviews increasingly incentivized … and makes reviews a lot more favorable

Source: ReviewMeta – 7 million review sample [2].

What Amazon is doing to combat fake reviews

Quality customer reviews are integral to Amazon’s business model – it is therefore no surprise that Amazon is defending review integrity fiercely:

  • Law suits: In 2015-2016, Amazon sued both its own sellers sellers and more than 1,000 individuals for having solicited or provided fake reviews [5]. While helpful as a deterrent, suing all fake reviewers ex post is a quite resource intensive strategy.
  • “Verified Purchase”: Reviewers who Amazon can track in the system to have actually bought a product have a “verified purchase” tagged to their reviews. This will deter sellers from soliciting reviews, or at least so for high ticket items. Recently, sellers have found a way around: an elderly Boston couple started receiving countless smaller products from Amazon that they didn’t order — purchased by a seller who used their address to “verify” a purchase and earn the right to review [6].
  • “X# people found helpful”: Customers can up/downvote reviews that are found precise and helpful.
  • AI screen: Finally, Amazon uses AI to detect precise and trustworthy reviews and give them a preferential weight and placement [7].


* The site only analyses reviews reported by customers, which would most likely bias the result upwards.






[5] and




Reddit – Democratizing Online Content


Quantopian – Crowdsourcing the Alpha!

Student comments on Amazon reviews: Loved, but also to be trusted?

  1. Interesting post! Amazon takes the integrity of customer reviews extremely seriously. I worked on the Amazon Vine program this past summer. Vine enables sellers to pay for reviews, but Amazon manages the entire process to preserve the integrity of the reviews. For example, sellers send goods to Amazon and then Amazon sends the goods to the reviewer in order to prevent sellers from ever interacting directly with reviewers. Even with these measures in place though there definitely continues to be issues. I can’t imagine the elimination of all “fake” reviews will ever be achieved, but it will be interesting to see how Amazon leverages ever more sophisticated technology to help ensure reviews are genuine, especially given the importance the organization places on this.

  2. Interesting read and I guess it makes sense that an entire market is emerging for independent review sites that consumers place greater trust in. Specifically, “The Sweet Home” is one such review site, which does extensive product reviews on many products sold in Amazon’s marketplace. The company was acquired by the NYT and in the press release the newspaper cited the ïntegrity of Sweet Home’s approach as a fit with their own journalistic standards.

    1. Yes! The Sweet Home is pretty cool. I also stumbled upon and, where you can just copy paste in the Amazon URL and it will tell you an adjust star-rating (1-5) based on its algorithms for detecting fake reviews.

      1. That’s a great functionality. Could or has this been built into a service where you can browse a curated version / a true-er version of Amazon, (where the products you browse and their ratings have been verified)?
        That would be amazing. In general, Amazon has been called out a lot in recent years for their aggressive behavior towards their vendors, but in general I feel like they have not been called out enough for their aggressive and potentially value destroying behavior towards their own consumers – who are quite powerless in the shadow of its power.
        “Post-Amazon Revolution!”

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