Why and how do firms charge different prices for the same product?
Price discrimination, the conditions required for it, the degrees of price discrimination, and its effects on firms, consumers and economic welfare.
An answer to AQA A-Level Economics 4.1.5, covering price discrimination, the conditions required for it to work, the three degrees of price discrimination, and its effects on firms, consumers and economic welfare.
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What this dot point is asking
AQA wants you to define price discrimination, state the conditions needed for it, describe the three degrees, and evaluate its effects on firms, consumers and welfare. It is a natural extension of monopoly power and the PED-revenue link.
Definition and conditions
The profit logic rests on elasticity: the firm raises price in the inelastic market (where quantity falls little) and lowers it in the elastic market (where the lower price attracts many extra buyers), so total profit exceeds what a single price would earn.
The degrees of price discrimination
- First degree (perfect). The firm charges each consumer the maximum they are willing to pay, capturing the entire consumer surplus as profit. Hard to achieve in practice, but personalised online pricing and auctions move towards it.
- Second degree. Prices vary with the quantity or timing of purchase, for example bulk discounts, multi-buy offers, or off-peak energy and travel pricing.
- Third degree. Different prices are charged to separable groups based on an identifiable characteristic, such as student, adult and senior rail fares, set so the higher price falls on the more inelastic group.
Welfare effects
- For firms. Higher total revenue and supernormal profit from capturing consumer surplus. Extra profit may fund investment, supporting dynamic efficiency, or cross-subsidise loss-making services such as off-peak rural transport.
- For consumers. Those in the inelastic market pay more, losing consumer surplus; those in the elastic market may pay less, and some who were priced out at a single price can now afford the good, so output can rise.
- For welfare. Consumer surplus is transferred to producers (a distributional concern), so the overall effect is ambiguous and depends on whether total output rises and whether profits are reinvested or used to cross-subsidise.
Exam-style practice questions
Practice questions written in the style of AQA exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
AQA 20186 marksExplain the conditions necessary for a firm to be able to price discriminate, using a real-world example.Show worked answer →
A 6 mark question rewards the three conditions, explained and applied.
- Price-setting power
- The firm must have some monopoly power, otherwise competition forces a single price; a train operator on a route has this.
- Separable markets by elasticity
- It must be able to split consumers into groups with different price elasticities, for example commuters (inelastic, peak) and leisure travellers (elastic, off-peak).
- No resale (no seepage)
- It must prevent the low-price group reselling to the high-price group; a cheap off-peak ticket cannot be used at peak time.
Markers reward all three conditions, defined and tied to the example.
AQA 20229 marksAssess whether third-degree price discrimination by a profit-maximising firm benefits consumers.Show worked answer →
A 9 mark assessment question needs both sides and a judgement.
- Costs to consumers
- Inelastic-demand groups (peak commuters) pay more, losing consumer surplus that is transferred to the firm as profit.
- Benefits to consumers
- Elastic-demand groups may pay less; some priced out at a single price can now afford the good, raising output and access. Extra profit can cross-subsidise loss-making services or fund investment.
- Judgement
- The net effect is ambiguous: it harms inelastic groups but helps elastic ones and may raise total output. Whether consumers as a whole gain depends on the price gaps and on reinvestment. Markers reward a supported, two-sided answer.
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Sources & how we know this
- AQA A-level Economics (7136) specification — AQA (2015)