Oligopoly: d) Price discrimination

The idea

Price discrimination occurs when a firm charges different prices to different consumer groups for an identical good or service, for reasons unrelated to cost differences. To succeed, a firm must possess price-making power, separate the market into distinct groups with differing price elasticities of demand, and prevent resale (arbitrage). For example, train operators charge higher peak fares to commuters with inelastic demand, and lower off-peak fares to leisure travellers. This strategy allows firms to convert consumer surplus into producer surplus, increasing total profits. It can also benefit consumers by enabling lower-income groups to access services they otherwise could not afford, even though inelastic consumers pay higher prices.

What earns the marks

• Definition of price discrimination as charging different prices for the same product without cost justification.
• Identification of the necessary conditions: market power, market separation, and prevention of arbitrage.
• Explanation of how differing price elasticities of demand between sub-markets allow for profit maximisation.
• Analysis of the impact on consumer and producer surplus.
• Evaluation of the benefits and drawbacks for different consumer groups and the firm.

Common mistakes and how to put them right

• Confusing price discrimination with product differentiation.

  Put it right: Price discrimination involves the exact same product, whereas product differentiation involves charging different prices for slightly different products.

• Forgetting the condition of preventing resale.

  Put it right: State that arbitrage must be prevented, otherwise consumers in the cheaper market will sell to those in the expensive market.

• Assuming price discrimination always harms consumers.

  Put it right: Recognise that consumers with highly elastic demand may benefit from lower prices and increased access to the market.

Exam tips

• Always state the three necessary conditions for price discrimination when defining the concept in an extended response.
• Use a clear, real-world example, such as student discounts or peak and off-peak train travel, to illustrate market separation.
• When evaluating, contrast the loss of consumer surplus for inelastic buyers with the potential cross-subsidisation of loss-making services.