Cambridge IGCSE Economics: The market economic system and market failure (0455)

This guide teaches sections 2.9 and 2.10 of the Cambridge IGCSE Economics 0455 syllabus for examination in 2026: the market economic system (2.9.1 and 2.9.2) and market failure (2.10.1 to 2.10.3). Economics 0455 is not tiered, so everyone studies all of it. Every figure and place in the worked examples is invented for practice and is not a real statistic.

Related pages: revision notes for this unit, practice questions for this unit, the wider allocation of resources study guide, the Cambridge IGCSE Economics hub, the printable checklist and the free diagnostics. The mixed economic system and the policies that correct failures belong to section 2.11, which has its own pages.

Outcomes this guide teaches

Section	Outcome
2.9.1	Define the market economic system
2.9.2	Advantages and disadvantages of the market economic system, with examples of how it works in different countries
2.10.1	Define market failure and the key terms: public good, merit good, demerit good, private, external and social benefits and costs
2.10.2	Causes of failure in the syllabus areas (public goods, merit and demerit goods, external costs and benefits, monopoly abuse, factor immobility), illustrated within those areas
2.10.3	Consequences: too much demerit-good and external-cost output consumed, too little merit-good and external-benefit output consumed

The syllabus states that demand and supply diagrams for market failure are not required. This guide therefore uses words and small tables.

2.9.1 The market economic system

A market economic system is one in which the decisions about what, how and for whom to produce are made by buyers and sellers through the price mechanism, with private individuals and firms owning most resources. Households choose what to buy, firms choose what to sell, and prices adjust until the two sides meet.

Worked example: a price signal. In Country A (invented), demand for Good X rises, so its price goes from 20 to 26. The price rise is 6 ÷ 20 × 100 = 30%. Each unit costs 18 to make.

	Before	After
Price	20	26
Profit per unit	2	8
Units sold	1,000	1,200
Total profit	2,000	9,600

Profit has risen from 2,000 to 9,600. Higher profit pulls firms and workers towards Good X, and output expands. Nobody planned this. The price signal moved resources to where consumers wanted them.

2.9.2 Advantages and disadvantages

Advantages	Disadvantages
Consumer choice: firms compete to supply what people will pay for	Market failure: public goods may not be provided, and external costs are ignored
Efficiency: competition pushes firms to cut costs	Inequality: those with little income have little buying power, so their wants are not met
Quick response: prices signal changes in tastes and costs	Monopoly power may arise and raise prices
Incentives: profit rewards effort and risk-taking	Too little of merit goods and too much of demerit goods is bought
Little need for a central planner	Unemployment and insecurity when firms close

Examples from different countries. No country has a pure market system. Economies differ in how far they rely on markets. To show this with illustrative cases: in Country B (invented) most goods, housing and healthcare are bought and sold privately, so choice is wide but poorer households struggle to pay for healthcare. In Country C (invented) markets set most prices, yet the state provides defence and basic schooling, so the market failures of public and merit goods are reduced. For your exam, use any real examples you have studied in class, and say how the market works there rather than only naming the country.

Evaluation. Whether advantages outweigh disadvantages depends on the product (a market works well for clothes, badly for street lighting), the incomes in the country, and how much competition exists. A balanced answer gives both sides and then judges.

2.10.1 Market failure and key terms

Market failure occurs when the free market fails to allocate resources efficiently, so that too much of some goods and too little of others is produced and consumed. The result is a misallocation of resources.

Term	Meaning
Private cost	Cost to the buyer or producer who takes the decision
External cost	Cost imposed on third parties who are not part of the decision, such as pollution
Social cost	Total cost to society: private cost + external cost
Private benefit	Benefit to the buyer or producer
External benefit	Benefit received by third parties
Social benefit	Total benefit to society: private benefit + external benefit
Public good	A good that is non-excludable (you cannot stop non-payers using it) and non-rival (one person’s use does not reduce another’s)
Merit good	A good that society judges to be beneficial, often with external benefits, that would be under-consumed if left to the market
Demerit good	A good that harms the user and often others, that would be over-consumed if left to the market

2.10.2 Causes of market failure

Public goods

Street lighting, flood defences and national defence are typical examples. Because non-payers cannot be excluded, people have an incentive to free ride: enjoy the good while others pay. Firms cannot earn enough revenue, so the market does not provide it.

Worked example. A town of 200 households (invented) needs lighting costing 6,000 a year. The fair share is 6,000 ÷ 200 = 30 each. If payment is voluntary and only 50 households pay, revenue is 50 × 30 = 1,500, which is 25% of the cost. The shortfall is 4,500 and 150 households are free riders. The lights are not built even though every household would gain.

Merit goods and external benefits

Vaccination, education and training have private benefits to the user and external benefits to others. People often undervalue them because of imperfect information, or cannot afford them.

Worked example. A vaccine costs 45 per dose (invented). Three groups of people in Country D decide whether to buy.

Group	People	Private benefit	External benefit	Social benefit
1	600	60	25	85
2	800	40	25	65
3	600	20	20	40

Individuals buy only if private benefit is at least 45, so only Group 1 buys: 600 doses. Society gains if social benefit is at least 45, so Groups 1 and 2 should buy: 1,400 doses. Consumption is 800 doses too low, which is 57.1% below the socially best level. The gain lost is 800 × (65 − 45) = 16,000. Group 3 should not be vaccinated at this cost, because 40 is below 45.

Demerit goods and external costs

A demerit good harms the consumer, who may underestimate the harm. External costs arise when producers or consumers do not pay for damage to others, such as river pollution or noise.

Worked example. A paper mill (invented) has private costs of 60 per tonne and imposes clean-up costs of 15 per tonne on a town. Social cost is 60 + 15 = 75. It makes 4,000 tonnes and sells at 70.

Item	Per tonne	4,000 tonnes
Private cost	60	240,000
External cost	15	60,000
Social cost	75	300,000

External cost is 15 ÷ 75 = 20% of social cost. Private profit is (70 − 60) × 4,000 = 40,000. Once external cost is counted, the net result for society is (70 − 75) × 4,000 = −20,000. The firm reports a profit, but society makes a loss.

Abuse of monopoly power

A firm with few or no competitors, protected by barriers to entry, can restrict output and raise price. Competition would force lower prices and better service.

Worked example. A cement market in Region R (invented) has a unit cost of 4.00. Under competition the price is 5.00 and 10,000 units sell. After one firm takes over every producer the price is 7.50 and 7,000 sell.

• Price rises by 2.50 ÷ 5.00 = 50%; quantity falls by 30%.
• Revenue moves from 50,000 to 52,500, but profit moves from 1.00 × 10,000 = 10,000 to 3.50 × 7,000 = 24,500.

Consumers pay more and get less. Resources are under-used in this industry relative to what consumers would want.

Factor immobility

Factors of production cannot always move to where they are most needed. Geographical immobility is when workers cannot or will not move region (family ties, housing costs). Occupational immobility is when workers lack the skills for jobs on offer.

Worked example. A mill closes in Town T (invented) and 500 workers lose jobs. A new warehouse takes 120. Of the remaining 380, a quarter (95) move to a city where 300 vacancies exist. Unemployed: 380 − 95 = 285, which is 57% of the 500. Unfilled vacancies: 300 − 95 = 205. Labour sits idle in one place while jobs go unfilled in another: a misallocation.

2.10.3 Consequences of market failure

When markets fail, the quantity bought and sold differs from the socially best quantity.

Type of good	What goes wrong	Result
Demerit good	Consumers underestimate harm	Over-consumption
Good with external costs	Producers or consumers ignore costs to others	Over-consumption (and over-production)
Merit good	Consumers undervalue benefits	Under-consumption
Good with external benefits	Others’ gains ignored	Under-consumption

Worked example of over-consumption. In Country E (invented) 8,000 units of a harmful product are bought a month, but the socially best amount is 5,000. Over-consumption is 3,000 units, 60% above the efficient level. Resources used for those units could have produced goods worth more to society.

Chain of reasoning. Choose a good, state who is affected, show why private decisions ignore it, state whether consumption is too high or too low, then state the misallocation: resources are used where social cost exceeds social benefit, or not used where social benefit exceeds social cost.

Evaluation. The size of the problem depends on how large the external effect is, how many people are affected, and whether people can be better informed. Some external effects are too small to matter.

Common errors

• Writing “social cost” when you mean “external cost”. External cost is only the third-party part.
• Saying a merit good is simply a good that is expensive. The test is society’s view of its benefit.
• Calling a toll road a public good. If non-payers can be excluded, it is not non-excludable.
• Giving over-consumption for a merit good. It is under-consumed.
• Stopping at “monopolies charge high prices” without saying that output is restricted.

Official syllabus

Cambridge IGCSE Economics 0455, syllabus for examination in 2026, Version 2, published by Cambridge University Press & Assessment (Cambridge Assessment International Education), sections 2.9 and 2.10.