Pearson Edexcel International GCSE Economics: The mixed economy and externalities (4EC1) – Revision Notes

These revision notes condense sections 1.1.5 (The mixed economy) and 1.1.6 (Externalities) of the Pearson Edexcel International GCSE Economics (4EC1) specification, Issue 3, February 2026. Full explanations and worked examples are in the study guide. Test yourself with the practice questions, tick off the checklist, see the course hub or try the free 10-minute diagnostics. The single tier of entry means no content is marked as higher or foundation. All numbers below are invented.

Definitions to learn

Term	Definition	Ref
Mixed economy	Resources are allocated by both the market (private sector) and the government (public sector)	1.1.5 a
Private sector	Part of the economy owned and run by individuals and firms	1.1.5 b
Public sector	Part of the economy owned and controlled by the government	1.1.5 b
Market failure	Resources are used inefficiently in a free market	1.1.5 e
Public good	A good with both characteristics: non-excludable and non-rival	1.1.5 g
Non-excludable	Nobody can be stopped from using it once it exists	1.1.5 g
Non-rival	Use by one person leaves the same amount for everyone else	1.1.5 g
Free rider problem	People use a good without paying, so private firms cannot cover costs and do not provide it	1.1.5 g
Privatisation	A business or asset moves from government ownership to private ownership	1.1.5 j
External cost	A cost of production that falls on a third party	1.1.6 a
External benefit	A benefit of consumption that goes to a third party	1.1.6 c

Public versus private sector

	Private	Public
Ownership	Individuals, shareholders	Government
Control	Owners and managers	Ministers and officials
Usual aim	Profit, growth	Welfare, access, meeting needs

Take care: this is the usual emphasis. A state-owned firm may be told to cover its costs, and a private firm may care about reputation.

What, how and for whom in a mixed economy

Question	Market answer	Government answer
What	What consumers will pay for, because demand signals profit	Public goods, and services such as education and healthcare; taxes and subsidies change the mix
How	Cheapest method that works	Rules on safety and pollution; public budgets for its own services
For whom	Those with income to pay	Taxes, benefits and free or cheap services shift goods towards lower incomes

Link in one line: market gives efficiency and choice; government adds fairness and fills gaps.

Market failure and intervention

• Market failure means an inefficient allocation of resources.
• Two causes in this unit: no provision (public goods) and wrong amount (externalities).
• Reasons to intervene: provide what the market will not, reduce harm, increase beneficial activity, help those who cannot pay.
• Tools: tax, subsidy, regulation, direct provision, ownership.
• Limit: intervention costs money and officials may get it wrong.

Public goods in steps

Method for “Explain why a good is a public good”:

1. Say it is non-excludable and explain: nobody can be stopped from using it.
2. Say it is non-rival and explain: use by one does not reduce use by others.
3. Link to free riding: people use it without paying.
4. Conclude: private firms cannot earn revenue, so the market does not provide it, and the government provides it using tax.

Examples: street lighting, flood defences, national defence. Not public goods: a toll bridge (excludable), an ordinary school place (limited and rival), a restaurant meal (rival and excludable).

Small worked reminder: a village of 50 households wants a drain costing 400. Voluntary scheme: only 3 give 10 each = 30, which is 370 short. A local tax of 400 ÷ 50 = 8 each pays for it.

Roles and importance of the sectors (1.1.5 h, i)

• Private sector: most goods and services bought by consumers.
• Public sector: public goods, and often education, healthcare, policing, some transport and utilities.
• Importance varies by economy. Measures: government spending as a share of output, share of workers employed by government, share of output from state-owned firms.
• Formula: government spending ÷ national output × 100. Example: 90 ÷ 360 × 100 = 25%.

Privatisation (1.1.5 j, k)

Group	Possible gain	Possible loss
Consumers	Quality, choice, lower prices if competition grows	Higher prices, reduced service in unprofitable areas
Workers	Higher pay in a growing firm	Redundancies, tougher conditions
Businesses	Profit motive, efficiency, freedom to invest	Shareholder pressure, competition
Government	Sale proceeds, lower subsidy	Loses future profits and direct control

Small worked reminders:

• Workforce 500 to 425: (425 − 500) ÷ 500 × 100 = −15%.
• Price 4.00 to 3.60: (3.60 − 4.00) ÷ 4.00 × 100 = −10%.
• Proceeds 60, subsidy saved 8 a year: 60 ÷ 8 = 7.5 years of subsidy.

Evaluation prompts: Is the firm a monopoly? Are there regulators? Which group is considered? Short run or long run?

Externalities (1.1.6)

	External cost	External benefit
Arises from	Production (or any activity that harms others)	Consumption
Examples	Pollution, congestion, environmental damage	Education, healthcare, vaccinations
Market result	Too much produced, because firm ignores the cost	Too little consumed, because buyers ignore the gain
Formula	Social cost = private cost + external cost	For benefits, add the external part to the private part to get the social benefit

In full, the benefit rule reads: social benefit = private benefit + external benefit. Rearranged: external cost = social cost − private cost; external benefit = social benefit − private benefit.

Method for externality calculations:

1. Write the formula.
2. Substitute values per unit.
3. Multiply by the quantity if a total is asked.
4. State units and say who bears the cost or receives the benefit.

Small worked reminder: a quarry has private cost 40 per tonne and external cost 12 per tonne for dust. Social cost = 40 + 12 = 52 per tonne. For 500 tonnes, external cost = 12 × 500 = 6,000.

Chain for an external cost: firm ignores harm, so its cost looks low, so it supplies too much, so society suffers net loss. A tax of 12 per tonne would make the firm pay the external cost.

Chain for an external benefit: buyer counts only own gain, so demand is low, so too little is bought, so society misses out. A subsidy or free provision can raise the amount.

Building a longer answer

For an “explain” or “evaluate” question, use a short chain: point, development, link to the question, then a judgement if asked.

• Point: privatisation may raise prices for consumers.
• Development: a private owner seeks profit, so it may raise fares or cut unprofitable services.
• Link: this matters most if the firm has no competitors.
• Judgement: the effect on consumers depends on competition, so the gain to the government must be weighed against the loss to consumers.

Use the same pattern for externalities: name the third party, say what they gain or lose, say what the decision-maker ignores, and state the result for the amount produced or consumed.

Must-know distinctions

• Non-excludable (cannot stop use) versus non-rival (use does not reduce supply). Both are needed.
• Public good (a type of good) versus public sector (who owns and runs).
• Public sector provision versus privatisation: the first is government supply, the second moves ownership away from government.
• Private cost (to the producer) versus social cost (private plus external).
• External cost of production versus external benefit of consumption: learn the pairing the specification uses, and keep the wording of each definition separate.

Quick self-test

1. Define a mixed economy.
2. State the two characteristics of a public good.
3. A good has private cost 75 and external cost 30 per unit. Find the social cost.
4. Social cost is 140 and private cost is 90. Find the external cost.
5. A vaccination has private benefit 20 and external benefit 35. Find the social benefit.
6. Government spending is 90 and national output is 360. Calculate the public sector share.
7. A privatised firm cuts its workforce from 500 to 425. Find the percentage change.
8. Give two examples of external benefits.
9. A firm makes 500 units, each with an external cost of 18. Find the total external cost.
10. Explain in one sentence why a free rider problem stops the market providing a good.

Answers

1. An economy where resources are allocated by both the private sector (the market) and the public sector (the government).
2. Non-excludable and non-rival.
3. 75 + 30 = 105.
4. 140 − 90 = 50.
5. 20 + 35 = 55.
6. 90 ÷ 360 × 100 = 25%.
7. (425 − 500) ÷ 500 × 100 = −15%, a fall of 15%.
8. Any two from education, healthcare, vaccinations.
9. 18 × 500 = 9,000.
10. People can use the good without paying, so firms cannot earn enough revenue to cover costs and do not supply it.

Where marks are usually lost

• Quoting just one characteristic of a public good, or confusing non-rival with non-excludable.
• Saying that any state-provided service is a public good.
• Defining an externality without mentioning a third party.
• Mixing the formulae, for example adding external cost to private benefit.
• Giving an example with no reasoning, such as “pollution” with no explanation of who bears the cost.
• Writing that privatisation is always good or always bad, with no condition or conclusion.
• Listing effects on consumers, workers, businesses and government without saying which are gains and which are losses.
• Leaving out units, or forgetting to multiply by the quantity when a total is asked for.

Official syllabus

Pearson Edexcel International GCSE Economics (4EC1) specification, Issue 3, February 2026, published by Pearson Education Limited, sections 1.1.5 and 1.1.6.