Which? carried out a behavioural experiment which involved simulating fake reviews and endorsement labels and found they were hugely effective at manipulating consumers into picking Don’t Buy products instead of better quality alternatives.

Don’t Buy products are items that Which?’s independent lab tests have found to be of such poor quality that they should be avoided at all costs.

Which? found that every single one of the fake review scenarios it tested had adverse effects on consumer behaviour and, in the worst instance, demand for products boosted by these techniques increased by more than 136%.

The Competition and Markets Authority (CMA) recently announced an investigation into misleading online reviews. Which? says its investigation reinforces the need for the probe and urges the regulator to take the strongest possible action against sites that fail to tackle this problem.

Shopping task research

Which? asked nearly 10,000 people to complete a shopping task using images designed to look like the Amazon website.

Pages and content that were shown to participants as part of the survey were not real Amazon pages or content.

Amazon was chosen as it is the UK’s largest online shopping platform and was likely to be familiar to the greatest number of consumers. But Which? believes the findings of the experiment are equally applicable to other online platforms hosting user-generated reviews.

Respondents were asked to pick one of three product types – headphones, dash cams, or cordless vacuum cleaners – where Which? had previously found evidence of fake reviews.

They were then randomly allocated into one of six groups to determine the type of fake review activity they would see, varying from inflated star ratings to fake review text (tactics commonly used by unscrupulous sellers), as well as the addition of a platform endorsement label.

Participants were shown five identically-priced products in their chosen category: a Which? Best Buy, three ‘fillers’ with mediocre reviews, and a Don’t Buy which may or may not have been manipulated by fake reviews.

They reviewed the information about the five products, including seven reviews for each, before deciding which they would most like to buy in real life.

People duped into buying Don’t Buy products

In the group that saw no fake reviews, one in 10 (10.5%) people chose a Don’t Buy product.

But in the group where fake review text was added to this product, with phrases such as “oh…WOW! I love when I’m about to review an awesome product” alongside inflated star ratings pushing it up the search results, 23% of people were duped into choosing the Don’t Buy product.

The situation was even worse when a platform endorsement label was added to fake review text and inflated star ratings.

It further increased the proportion of people choosing the Don’t Buy product to a quarter (25%). This represents a 136% increase to the group that wasn’t exposed to any fake review activity, demonstrating the risk of consumers being misled by a recommendation label underpinned by fake reviews.

Which? says the findings are particularly concerning as the consumer group’s previous research found the Amazon’s Choice endorsement label being applied to potentially poor quality products that appeared to have been artificially boosted by incentivised and fake reviews.

One group was even presented with reviews containing admissions that reviewers had been incentivised to leave positive reviews, with phrases such as “Very happy! Just waiting for the free gift as promised” and signs that positive reviews of completely different products had been hijacked.

Despite this, 22 per cent of the participants still chose the Don’t Buy product, a leap of 105% versus those who saw no fake review activity.

Reporting fake reviews

Consumers concerned about the authenticity of reviews left on a product, when they are looking at websites, are encouraged to report this to the online platform so that it can investigate.

Caroline Normand, Which? director of advocacy, says: “Which? has found categorical evidence that people are at huge risk of being misled by fake reviews, which is particularly worrying given people are shopping online more than ever during the coronavirus pandemic.

“Online platforms must put more effective measures in place to stop unscrupulous sellers gaming the system with ease, otherwise the CMA needs to take strong action against these major sites.”

An Amazon spokesperson said: “We want Amazon customers to shop with confidence knowing that the reviews they read are authentic and relevant. We have clear policies for both reviewers and selling partners that prohibit abuse of our community features, and we suspend, ban, and take legal action against those who violate these policies.”