Amazon bans biased reviews that have been influenced by brands

Posts written in exchange for free product or discount rated the item in the top 6% in its category, on average.

(Getty)

Amazon has banned “incentivised reviews” after analysis of over 7m posts proved they are significantly more favourable than those where no incentive was offered.

Typically, incentivised reviews involve a company offering their product for free or at a big discount if the recipient agrees to review it.

Analysis by ReviewMeta found that incentivised reviews gave an average score 4.74 out of five, compared to 4.36 for non-incentivised reviews. The difference is enough to move a product into the top five per cent in its category, from around halfway down the rankings, the company said.

Amazon has responded by banning incentivised reviews, except for those under its own Vine programme, which invites vetted and trusted reviewers to test products and provide feedback.

The online retailer said that although the Vine programme itself offered incentives, it had “important controls in place”, and is “especially valuable for getting early reviews on new products that have not yet been able to generate enough sales to have significant numbers of organic reviews”.

The company said that its Vine system was robust because: “Amazon – not the vendor or seller – identifies and invites trusted and helpful reviewers on Amazon to post opinions about new and pre-release products; we do not incentivise positive star ratings, attempt to influence the content of reviews, or even require a review to be written; and we limit the total number of Vine reviews that we display for each product.”

ReviewMeta appeared to agree with that stance in its analysis. “At first glance, it seems to be much better controlled than their “review club” counterparts.” Vine reviews actually have a lower average score than non-incentivised reviews.

Chee Chew, vice-president of customer experience at Amazon, said incentivised reviews, “make up only a tiny fraction of the tens of millions of reviews on Amazon, and when done carefully, they can be helpful to customers by providing a foundation of reviews for new or less well-known products.“

In 2015, Amazon sued four companies it said had paid people to write reviews. It is also taking legal action against over 1,000 people it says have offered to submit positive reviews to the site in return for money.