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The economics of fake reviews

Imagine a situation where you are thinking of buying a good and so you go to an e-commerce marketplace such as Amazon, eBay, Etsy or Onbuy. How confident are you about the quality of the different brands/makes that are listed for sale on these digital platforms? How do you choose which product to buy? Is the decision strongly influenced by customer reviews and rating?

When a customer is choosing what to buy it raises an interesting question: to what extent can the true quality of the different goods/services be observed at the time of purchase? Although perfect observability is highly unlikely, the level of consumer information about a product’s true quality will vary between different types of transaction.

For example, when consumers can physically inspect and test/try a product in a shop, it can help them to make more accurate judgements about its quality and condition. This poses a problem for online sellers of high-quality versions of a good. Without the ability to inspect the item physically, consumers may be unsure about its characteristics. They may worry that the online description provided by the seller deliberately misrepresents the true quality of the item.

Consumers may have other concerns about the general reliability of online sellers. For example, in comparison to buying the product from a physical store, consumers may worry that:

  • They will have to wait longer to receive the good. In many cases, when consumers purchase a product from a high-street store, they can walk away with the item and start using it straight away. When purchasing on line, they may end up waiting weeks or even longer before the product is finally delivered.
  • It will be more difficult to return the product and get a refund.
  • They are more likely to come across fraudulent sellers who have set-up a fake website.

This greater level of uncertainty about the true characteristics of the product and the general reliability of the seller will have a negative impact on consumers’ willingness to pay for all goods. This impact is likely to be particularly strong for high-quality versions of a product. If consumers’ willingness to pay falls below the reservation price of many sellers of high-quality goods, then the market could suffer from adverse selection and market failure.

Are there any within-market arrangements that could help deal with this issue? One possibility is for sellers to signal the quality of their products by posting consumer ratings and reviews. If consumers see that a product has many positive ratings, then this will increase their confidence in the quality of the product and so increase their willingness to pay. This could then reduce both levels of asymmetric information and the chances of adverse selection occurring in the market,

There is survey evidence that many people do read consumer reviews when choosing products on line and are heavily influenced by the ratings.

The problem of fake reviews

However, when consumers look at these reviews can they be sure that they reflect consumers’ honest opinions and/or actual experience of using the good or service? Firms may have an incentive to manipulate and post fake reviews. For example, they could:

  • Deliberately fail to display negative reviews on their website while claiming that all reviews are published.
  • Use internet bots to post thousands of automated reviews.
  • Take positive reviews from competitors’ websites and post them on their own website.
  • Pay some customers and/or employees to write and post 5-star reviews on their own website.
  • Pay some customers and/or employees to write and post 1-star reviews on their competitors’ websites.
  • Set up a website that they claim is independent and use it to provide positive endorsements of their own products.

If the benefits of this type of behaviour outweigh the costs, then we would expect to see fake reviews posted on websites. If their use becomes widespread, then the value of posting genuine reviews will fall. The market may then settle into what economists call a ‘pooling equilibrium’.

What evidence do we have on the posting of fake reviews? Given their nature, it is difficult to collect reliable data and there are large variations in the reported figures. One recent study found evidence of fake reviews being purchased and posted for approximately 1500 products on Amazon.

Can consumers screen reviews and identify those that are more likely to be fake? The following are some tell-tale signs.

  • Products that receive a large number of very positive reviews over a short period (i.e. a few days). There are then long periods before the product receives another large number of positive reviews.
  • A high percentage of 5-star reviews. Two, three and four start reviews are more likely to be genuine.
  • Reviews that specifically mention a rival firm’s products.
  • Reviewers who have given very high ratings to large number of different products over a short period of time.
  • Reviews that include photos/videos.

Competition authorities around the world have been investigating the issue and the Competition and Markets Authority has announced plans to introduce new laws that make the purchasing and posting of fake reviews illegal.

Articles

Questions

  1. Outline different types of asymmetric information and explain the difference between adverse selection and moral hazard.
  2. Using a diagram, explain the impact of uncertainty over the quality of a good on consumers’ willingness to pay.
  3. Will consumers always face greater uncertainty over quality when purchasing goods on line rather than visiting the high street? Discuss your answer making reference to some specific examples.
  4. Using diagrams, explain how a market for high-quality versions of a good might collapse if there is asymmetric information. Using price elasticity of supply, explain the circumstances when the market is more likely to collapse.
  5. Discuss some of the benefits and costs for a firm of purchasing and posting fake reviews.