OCR GCSE Economics: Supply side policies and the limitations of markets (J205) – Revision Notes

Condensed notes for OCR GCSE (9-1) Economics (J205), specification Version 2.0 (June 2026), sections 3.7 and 3.8 in “Economic objectives and the role of government”. The specification is untiered. For full explanations and longer worked examples, read the study guide, then test yourself with the practice questions. Also see the OCR GCSE Economics hub, the printable checklist and the free 10-minute diagnostics. All figures below are invented and illustrative.

Key definitions

Term	Meaning
Supply side policy	Government action to raise the economy’s productive capacity
Externality	A cost or benefit to a third party, not reflected in the market price
Negative externality	A cost to third parties, such as pollution
Positive externality	A benefit to third parties, such as vaccination
Private cost / benefit	The cost or benefit to the buyer or seller directly involved
External cost / benefit	The cost or benefit that falls on others
Social cost	Private cost + external cost
Social benefit	Private benefit + external benefit
Opportunity cost	The next best alternative given up
State provision	The government supplies the good or service itself, funded by taxation

3.7 Supply side policies

Examples: education and training, infrastructure, support for research and technology, lower taxes on work or profits, less red tape, more competition.

Objective	Link to supply side policy
Growth	Higher productive capacity raises potential output
Low unemployment	Training and better job matching reduce structural unemployment
Price stability	Lower costs and higher productivity ease price pressure
Fair distribution	Skills can raise low pay; tax cuts for the rich may widen gaps

Link to section 3.1: the determinants of growth are investment, technology, workforce size, education and training, natural resources and government policies. Supply side policy works on these.

Evaluation chain for any supply side policy

1. Benefit: potential output rises, so growth is possible without inflation.
2. Cost: government spending or lost tax revenue, with an opportunity cost.
3. Limit: time lags, uncertainty, and winners and losers.
4. Judgement: sensible for long-run goals, too slow alone for a short-run problem.

Small worked reminder: output per worker

Country A has 1.5 million workers and output of £30bn. Output per worker = £30bn ÷ 1.5 million = £20,000. Output rises 1.5% to £30.45bn, so output per worker becomes £20,300. If the training costs £2bn a year and adds £2.6bn of output a year, the net gain is £2.6bn − £2bn = £0.6bn, but check the time lag and the opportunity cost.

3.8 Externalities

Markets overproduce goods with negative externalities and underproduce goods with positive externalities, because decision-makers ignore the effect on third parties.

	Negative externality	Positive externality
Example	Factory pollution, congestion	Education, vaccination
Market output compared with best for society	Too high	Too low
Fix	Reduce output	Increase output
Typical tools	Tax, regulation, information	Subsidy, state provision, information

Diagrams in words

• Negative externality: the social cost curve lies above the private cost (supply) curve. It meets demand at a lower quantity than the market equilibrium.
• Positive externality: the social benefit curve lies above the demand curve. It meets supply at a higher quantity than the market equilibrium.

Small numerical reminders

• Social cost: private cost £9 per unit + external cost £2.50 = £11.50 per unit. For 400 units, the external cost is 400 × £2.50 = £1,000.
• Social benefit: private benefit £14 + external benefit £3 = £17 per unit.
• Tax burden: a £3 tax raises the price from £12.00 to £13.80. Consumers bear £1.80 (60%), producers bear £1.20 (40%). If 5,000 units are sold, revenue is 5,000 × £3 = £15,000.
• Price elasticity of demand: price +10%, quantity −3%. PED = −3 ÷ 10 = −0.3, which is inelastic, so a tax cuts quantity by little.
• Opportunity cost: a £2.4m subsidy could instead buy 80 hospital beds at £30,000 each (£2.4m ÷ £30,000 = 80).

Method: finding the new equilibrium after a tax or subsidy

1. Write demand and supply as equations in price P.
2. For a per-unit tax, replace P in the supply equation by (P − tax). For a per-unit subsidy, replace P by (P + subsidy).
3. Set quantity demanded equal to quantity supplied and solve for P, then find Q.
4. Compare with the original equilibrium, and multiply the tax or subsidy by the new quantity to find revenue or cost.

Tax reminder (illustrative market). Demand is Qd = 1,200 − 30P and supply is Qs = 30P. Without tax: 1,200 = 60P, so P = £20 and Q = 600. With a £6 tax, supply is 30(P − 6), so 1,200 − 30P = 30P − 180 and 60P = 1,380. Then P = £23 and Q = 510. Consumers pay £3 more, producers receive £17 (£3 less). Tax revenue is 510 × £6 = £3,060. If each unit carries £6 of external cost, the cost avoided is (600 − 510) × £6 = £540.

Subsidy reminder (illustrative market). Demand is Qd = 800 − 10P and supply is Qs = 15P. Without subsidy: 800 = 25P, so P = £32 and Q = 480. With a £5 subsidy, supply is 15(P + 5), so 800 − 10P = 15P + 75 and 25P = 725. Then P = £29 and Q = 510. Buyers pay £3 less, providers receive £34 (£2 more). The cost to government is 510 × £5 = £2,550. The subsidy is paid on all 510 units, not only the 30 extra ones.

Command words in this unit

The specification defines the command words, and each needs a different answer.

Command word	What the specification asks for
Explain	State a definition, explain a concept or give an example, and apply it to the context
Analyse	Present a logical chain of reasoning
Calculate	Apply quantitative skills
Evaluate	Weigh up both sides or compare alternatives, and reach a supported judgement

For example, “explain how a tax reduces pollution” needs the chain cost up, supply down, price up, quantity down. “Evaluate” needs that chain plus the costs and limits, and a final choice.

Policy toolkit

Policy	How it works	Main benefit	Main cost or limit
Taxation	Raises cost, cuts output	Raises revenue; price signal	External cost hard to measure; can hit poor hardest
Subsidy	Lowers cost, raises output	Makes good cheaper; more consumed	Taxpayer cost; paid on units bought anyway
State provision	Government supplies directly	Access for all; large external benefit	Costly; opportunity cost; overuse if free
Legislation and regulation	Bans or limits activity	Certain, direct	Enforcement cost; evasion; higher business costs
Information provision	Changes attitudes	Cheap; keeps choice	Slow; uncertain; may be ignored

Method: evaluating a policy in five steps

1. State what the policy does to cost, price or behaviour.
2. Explain the effect on output and on the externality.
3. Name the cost, including opportunity cost, and who pays.
4. Add a limit specific to the context, such as elasticity, enforcement or time.
5. Reach a judgement and give a reason, perhaps recommending a combination.

Must-know distinctions

• Externality (third party) versus private cost (buyer or seller).
• Tax (cuts output of a negative externality) versus subsidy (raises output of a positive one).
• Supply side policy (long-run capacity) versus demand-side policy (short-run spending).
• Regulation (rules) versus information (persuasion).
• State provision (government supplies) versus subsidy (government pays part of the price).

Quick self-test

1. Define a positive externality.
2. State two supply side policies.
3. Give one way supply side policy can reduce unemployment.
4. A firm’s private cost is £15 per unit and the external cost is £4. State the social cost.
5. In a market, a £5 tax raises the price from £20 to £22. Calculate the share of the tax paid by consumers.
6. A price rise of 8% leads to a fall in quantity of 2%. Calculate price elasticity of demand.
7. Which is more likely to be overproduced: a good with a negative externality or a positive one?
8. Give one opportunity cost of a government subsidy.
9. Give one limitation of information provision.
10. Name the policy where government supplies the good directly.

Answers

1. A benefit to a third party that is not reflected in the market price.
2. For example, education and training, and investment in transport.
3. Training raises skills, which helps structurally unemployed workers find jobs.
4. £15 + £4 = £19.
5. Consumers pay £2 more of the £5 tax, which is 2 ÷ 5 = 40%.
6. −2 ÷ 8 = −0.25.
7. The good with a negative externality.
8. The money could have been spent on hospitals, schools or tax cuts instead.
9. It is slow and uncertain, as people may ignore it.
10. State provision.

Where marks are usually lost

• Defining an externality without mentioning a third party.
• Describing a policy without explaining its effect on output.
• Giving an evaluation point without linking it to the context.
• Forgetting opportunity cost when asked about costs.
• Treating a subsidy as costless because the producers receive the money.
• Saying a tax is always effective, without considering inelastic demand.
• Listing supply side policies without linking them to an objective.
• Finishing an evaluation with no judgement.

Official syllabus

OCR GCSE (9-1) Economics (J205), specification Version 2.0 (June 2026), first assessment 2019, published by OCR. Sections 3.7 and 3.8.