Unit 3 · Government Microeconomic Intervention (AS & A Level)
The Complete Cambridge International AS & A Level Economics (9708) Guide · Cambridge International AS & A Level Economics (9708)Unit 3 · Government Microeconomic Intervention (AS & A Level)
- The Complete Cambridge International AS & A Level Economics (9708) Guide
- Cambridge International AS & A Level Economics (9708)
- 6 sections
Cambridge International does not publish a per-unit weighting for this exam. Exam structure (official): AS Level: AS Level Multiple Choice (60 min, 30 questions, 33%) · AS Level Data Response And Essays (120 min, 67%); A Level: AS Level Multiple Choice (60 min, 30 questions, 17%) · AS Level Data Response And Essays (120 min, 33%) · A Level Multiple Choice (75 min, 30 questions, 17%) · A Level Data Response And Essays (120 min, 33%). Be ready to carry the same unit skills and representations into a complete answer on every paper. The vocabulary spine is indirect tax, tax incidence, subsidy, maximum price, minimum price, buffer stock, direct provision, transfer payment, progressive tax, wealth. Revise them through indirect taxes, subsidies, price controls, and redistribution: define the relationship, identify what changes, and keep the comparison needed for the disposable-cup tax wedge during recall.
- How Cambridge International AS & A Level Economics (9708) assesses this Cambridge International publishes no per-unit percentage for Cambridge International A Level Economics; Paper 1 accounts for 33% of the AS Level total and 17% of the A Level total. · AS Level: AS Level Multiple Choice (60 min, 30 questions, 33%) · AS Level Data Response And Essays (120 min, 67%) | A Level: AS Level Multiple Choice (60 min, 30 questions, 17%) · AS Level Data Response And Essays (120 min, 33%) · A Level Multiple Choice (75 min, 30 questions, 17%) · A Level Data Response And Essays (120 min, 33%) · show the model with Quantity and Price graph, D, S1, S2 + tax labels, Quantity is horizontal and Price is vertical., Labor and Wage rate graph, D1, D2, S labels, Labor is horizontal and Wage rate is vertical.
- Key skills Reasons for Government Intervention in Markets, Indirect Taxes and Subsidies: Impact and Incidence, Maximum and Minimum Prices, Buffer Stocks, Direct Provision and Provision of Information, Addressing Income and Wealth Inequality, Government Policies to Correct Market Failure, and Government Failure (A Level), Equity and Redistribution of Income and Wealth (A Level), Labor Market Forces: Demand for and Supply of Labor and Marginal Revenue Product (A Level), Wage Determination, Wage Differentials, Transfer Earnings and Economic Rent (A Level)
- How to study for Unit 3 This page turns Quantity and Price graph, D, S1, S2 + tax labels, Quantity is horizontal and Price is vertical., Labor and Wage rate graph, D1, D2, S labels, Labor is horizontal and Wage rate is vertical. into one route: After the cup tax, solve 100−Q=32+Q to obtain Q=34..
- The organizing decision The disposable-cup diagram makes the tax wedge visible: S1 gives the pre-tax supply price, S2 adds 12, and the post-tax quantity is 34.
- What A Level adds The labor-market graph places employment on the horizontal axis and the wage rate vertically. Topics: Government Policies to Correct Market Failure, and Government Failure; Equity and Redistribution of Income and Wealth; Labor Market Forces: Demand for and Supply of Labor and Marginal Revenue Product; Wage Determination, Wage Differentials, Transfer Earnings and Economic Rent.
What Cambridge International AS & A Level Economics (9708) Unit 3 covers
Use this map to connect each assessed skill to the relationship or representation that makes it visible.
Reasons for Government Intervention in Markets
indirect tax; tax incidence; subsidy02Indirect Taxes and Subsidies: Impact and Incidence
indirect tax; tax incidence; subsidy03Maximum and Minimum Prices, Buffer Stocks, Direct Provision and Provision of Information
indirect tax; tax incidence; subsidy04Addressing Income and Wealth Inequality
indirect tax; tax incidence; subsidy05Government Policies to Correct Market Failure, and Government Failure (A Level)
market failure; government failure; external cost06Equity and Redistribution of Income and Wealth (A Level)
market failure; government failure; external cost07Labor Market Forces: Demand for and Supply of Labor and Marginal Revenue Product (A Level)
market failure; government failure; external cost08Wage Determination, Wage Differentials, Transfer Earnings and Economic Rent (A Level)
market failure; government failure; external costCambridge International does not publish a per-unit weighting for this exam.
Official unit name and weighting: Cambridge International syllabus.
Government Microeconomic Intervention
Connect the published share to the unit model
The vocabulary spine is indirect tax, tax incidence, subsidy, maximum price, minimum price, buffer stock, direct provision, transfer payment, progressive tax, wealth. Revise them through indirect taxes, subsidies, price controls, and redistribution: define the relationship, identify what changes, and keep the comparison needed for the disposable-cup tax wedge during recall.
The disposable-cup diagram makes the tax wedge visible: S1 gives the pre-tax supply price, S2 adds 12, and the post-tax quantity is 34. Buyer and seller prices must not be collapsed into one figure.
The decision that organizes this unit
Define the system and choose the route before calculating
The disposable-cup diagram makes the tax wedge visible: S1 gives the pre-tax supply price, S2 adds 12, and the post-tax quantity is 34.
After the cup tax, solve 100−Q=32+Q to obtain Q=34.
Mechanism route and repair branches
Relationships to preserve
- Begin intervention analysis from the untaxed cup equilibrium, Q=40 and P=60.
- Tax revenue uses the tax per unit multiplied by the quantity traded after tax.
- A maximum price, minimum price, buffer stock, direct provision, and transfer payment operate through different mechanisms.
- Separate the labor-market mechanism from the externality formulas.
- Pollution permits and property rights address environmental incentives, whereas poverty measures concern income standards.
- For labor questions, use MRP for the demand-side value of an extra worker and economic rent for earnings above transfer earnings.
Representations to read
- Quantity and Price graph
- D, S1, S2 + tax labels
- Quantity is horizontal and Price is vertical.
- Labor and Wage rate graph
- D1, D2, S labels
- Labor is horizontal and Wage rate is vertical.
Branches to reject
- The buyer price can be confused with the seller receipt.
- Incidence is not determined by who sends the tax payment.
- A control matters only relative to equilibrium.
- Private cost can omit harm imposed on others.
- Productivity alone does not give the value of labor demand.
- All earnings can be mistaken for the minimum supply payment.
| Key concept | Why it's hard | What scores |
|---|---|---|
| indirect tax | The buyer price can be confused with the seller receipt. | Show the 12-unit wedge between 66 and 54 at Q=34. |
| tax incidence | Incidence is not determined by who sends the tax payment. | Compare the post-tax buyer and seller prices with P=60. |
| minimum price | A control matters only relative to equilibrium. | State whether the floor is binding before tracing surplus. |
How Cambridge International AS & A Level Economics (9708) assesses Government Microeconomic Intervention (AS & A Level)
What a complete response must make visible
Match the task to evidence that a reader can audit, then check the most likely reasoning failure before finalizing the response.
| Task | Evidence to show | Hurdle |
|---|---|---|
| Reasons for Government Intervention in Markets | indirect tax; tax incidence; subsidy | The buyer price can be confused with the seller receipt. |
| Indirect Taxes and Subsidies: Impact and Incidence | indirect tax; tax incidence; subsidy | Incidence is not determined by who sends the tax payment. |
| Maximum and Minimum Prices, Buffer Stocks, Direct Provision and Provision of Information | indirect tax; tax incidence; subsidy | A control matters only relative to equilibrium. |
| Addressing Income and Wealth Inequality | indirect tax; tax incidence; subsidy | Private cost can omit harm imposed on others. |
| Government Policies to Correct Market Failure, and Government Failure (A Level) | market failure; government failure; external cost | Productivity alone does not give the value of labor demand. |
| Equity and Redistribution of Income and Wealth (A Level) | market failure; government failure; external cost | All earnings can be mistaken for the minimum supply payment. |
| Labor Market Forces: Demand for and Supply of Labor and Marginal Revenue Product (A Level) | market failure; government failure; external cost | The buyer price can be confused with the seller receipt. |
| Wage Determination, Wage Differentials, Transfer Earnings and Economic Rent (A Level) | market failure; government failure; external cost | Incidence is not determined by who sends the tax payment. |
AS micro intervention: draw and solve the model
Read each question as it appears on the exam paper, choose your answer, then tap it to see the feedback.
Practice 1: Specific tax and tax incidence
A city places a specific tax of 12 currency units on each disposable cup sold.
Before tax, demand is P = 100 − Q and supply is P = 20 + Q. The tax changes supply to P = 32 + Q. (a) Calculate the pre-tax equilibrium. (b) Calculate the post-tax quantity, the price paid by buyers and the price received by sellers. (c) Show the tax wedge on a demand-and-supply diagram.
Show your working and label all relevant prices and quantities.
A. Solve 100 − Q = 32 + Q to get Q = 34, use demand to find buyers pay 66, then subtract 12 so sellers receive 54.
✅ Correct! 😊 This finds the post-tax traded quantity and preserves the 12-unit vertical wedge. It correctly distinguishes the market price paid from the net amount sellers keep.
B. Keep Q = 40, add the tax to P = 60, and say both buyers and sellers face P = 72.
❌ Not quite 😭 This ignores the fall in quantity when supply shifts. It also collapses the buyer price and seller receipt into one number.
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C. Solve 100 − Q = 20 + Q to get Q = 40 and subtract 12 from quantity, giving Q = 28.
❌ Not quite 😭 A per-unit tax shifts the supply price, not quantity directly. Subtracting 12 from the original quantity does not locate the new equilibrium.
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D. Solve 100 − Q = 32 + Q to get Q = 34, then say sellers receive 66 because they send the tax payment.
❌ Not quite 😭 Who remits the tax does not determine incidence or the seller receipt. Sellers keep the buyer price minus the 12-unit tax, which is 54.
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Full explanation
- Step 1Before tax, 100 − Q = 20 + Q gives Q = 40 and P = 60.
- Step 2After tax, equate demand with shifted supply: 100 − Q = 32 + Q, so Q = 34.
- Step 3Demand gives the buyer price: P = 100 − 34 = 66.
- Step 4Subtract the 12-unit tax from 66, so sellers receive 54; show this vertical wedge at Q = 34.
Practice 2: A binding minimum price
The equilibrium price of an agricultural product is 24 currency units.
The government introduces a legal minimum price of 30 currency units. At that price, quantity supplied is greater than quantity demanded. What is the immediate market outcome?
Choose one answer.
A. A surplus, because the minimum price is above equilibrium and is binding
✅ Correct! 😊 The floor prevents the price falling to equilibrium. At the higher legal price, excess supply creates a surplus.
B. A shortage, because every minimum price increases demand
❌ Not quite 😭 A higher price normally reduces quantity demanded and raises quantity supplied. The scenario explicitly states that supply exceeds demand.
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C. No effect, because all price controls are non-binding
❌ Not quite 😭 A minimum price above the equilibrium is binding. Only a floor at or below equilibrium would leave the market price unchanged.
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D. A new equilibrium at 30, because quantity supplied must equal quantity demanded at any legal price
❌ Not quite 😭 A legal price does not guarantee market clearing. Here the quantities differ, so 30 is a controlled price with surplus output.
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Full explanation
- Step 1Compare the minimum price of 30 with the equilibrium price of 24.
- Step 2Because the floor is above equilibrium, it is binding and prevents the price falling to 24.
- Step 3At 30, quantity supplied exceeds quantity demanded, so the market has a surplus.
Key terms for Unit 3: Government Microeconomic Intervention (AS & A Level)
Models, uses, and boundaries
- Tax revenue
- Tax revenue equals the per-unit tax multiplied by the taxed quantity sold. Tax revenue equals the per-unit tax multiplied by the taxed quantity sold. In the cup market, the relevant quantity is the post-tax Q.
- Subsidy cost
- Subsidy cost multiplies the subsidy per unit by the quantity receiving it. Subsidy cost multiplies the subsidy per unit by the quantity receiving it. Do not substitute the untaxed quantity unless it remains the traded amount.
- The average tax rate expresses total tax as a percentage of income
- The average tax rate expresses total tax as a percentage of income. The average tax rate expresses total tax as a percentage of income. It describes the overall burden, not the rate on the next unit of income.
- The marginal tax rate
- The marginal tax rate divides the change in tax by the change in income. The marginal tax rate divides the change in tax by the change in income. Both changes must refer to the same income interval.
- Marginal social cost
- Marginal social cost adds marginal external cost to marginal private cost. Marginal social cost adds marginal external cost to marginal private cost. Omitting MEC understates the cost borne by society.
- Marginal social benefit
- Marginal social benefit adds marginal external benefit to marginal private benefit. Marginal social benefit adds marginal external benefit to marginal private benefit. The external component belongs only when others receive that benefit.
- Marginal revenue product
- Marginal revenue product multiplies marginal physical product by marginal revenue. Marginal revenue product multiplies marginal physical product by marginal revenue. It values the extra output attributable to the factor.
- Economic rent
- Economic rent subtracts transfer earnings from actual earnings. Economic rent subtracts transfer earnings from actual earnings. Transfer earnings are the minimum needed to keep the factor in its current use.
Cambridge International AS & A Level Economics (9708) Unit 3 FAQ
How much of Cambridge International AS & A Level Economics (9708) does Unit 3 carry?
Cambridge International does not publish a per-unit weighting for this exam.
What is the first move on a Government Microeconomic Intervention (AS & A Level) problem?
After the cup tax, solve 100−Q=32+Q to obtain Q=34.
Which relationships should I preserve?
Begin intervention analysis from the untaxed cup equilibrium, Q=40 and P=60. Tax revenue uses the tax per unit multiplied by the quantity traded after tax. A maximum price, minimum price, buffer stock, direct provision, and transfer payment operate through different mechanisms. Separate the labor-market mechanism from the externality formulas. Pollution permits and property rights address environmental incentives, whereas poverty measures concern income standards. For labor questions, use MRP for the demand-side value of an extra worker and economic rent for earnings above transfer earnings.
Which representations should I practice?
Practice moving among Quantity and Price graph, D, S1, S2 + tax labels, Quantity is horizontal and Price is vertical., Labor and Wage rate graph, D1, D2, S labels, Labor is horizontal and Wage rate is vertical..
What error should I check before submitting an answer?
Check for The buyer price can be confused with the seller receipt.; Incidence is not determined by who sends the tax payment.; A control matters only relative to equilibrium.; Private cost can omit harm imposed on others.; Productivity alone does not give the value of labor demand.; All earnings can be mistaken for the minimum supply payment..
Evidence workshop
Continue from the free model into complete practice
The full unit guide continues with the chapter’s worked examples, figures, scoring tables, and answer checks.
- AS micro intervention: connect direction and magnitude
- AS micro intervention: draw and solve the model
- AS micro intervention: build the argument
- Government Microeconomic Intervention: connect the model
Full unit practice. Open the complete guide for the full evidence workshop and synthesis.
Related Cambridge International AS & A Level Economics (9708) unit guides
Cambridge International AS & A Level Economics (9708) Exam Guide & Review
The whole exam and its official unit sequence.01Basic Economic Ideas and Resource Allocation
Cambridge International does not publish a per-unit weighting for this exam.02The Price System and the Microeconomy (AS & A Level)
Cambridge International does not publish a per-unit weighting for this exam.04The Macroeconomy (AS & A Level)
Cambridge International does not publish a per-unit weighting for this exam.05Government Macroeconomic Intervention (AS & A Level)
Cambridge International does not publish a per-unit weighting for this exam.06International Economic Issues (AS & A Level)
Cambridge International does not publish a per-unit weighting for this exam.How to study Cambridge International AS & A Level Economics (9708) Unit 3
Start with the organizing decision
Before solving, restate the decision in operational terms: The disposable-cup diagram makes the tax wedge visible: S1 gives the pre-tax supply price, S2 adds 12, and the post-tax quantity is 34.. Your first written move should be to After the cup tax, solve 100−Q=32+Q to obtain Q=34..
Practice the same idea in several representations
Rotate through Quantity and Price graph, D, S1, S2 + tax labels, Quantity is horizontal and Price is vertical., Labor and Wage rate graph, D1, D2, S labels, Labor is horizontal and Wage rate is vertical.. Use each representation to practice Reasons for Government Intervention in Markets, Indirect Taxes and Subsidies: Impact and Incidence, Maximum and Minimum Prices, Buffer Stocks, Direct Provision and Provision of Information, Addressing Income and Wealth Inequality, Government Policies to Correct Market Failure, and Government Failure (A Level), Equity and Redistribution of Income and Wealth (A Level), Labor Market Forces: Demand for and Supply of Labor and Marginal Revenue Product (A Level), Wage Determination, Wage Differentials, Transfer Earnings and Economic Rent (A Level), and explain what stays invariant when the surface form changes.
Turn each error into a repair check
After every attempt, audit the response for The buyer price can be confused with the seller receipt.; Incidence is not determined by who sends the tax payment.; A control matters only relative to equilibrium.; Private cost can omit harm imposed on others.; Productivity alone does not give the value of labor demand.; All earnings can be mistaken for the minimum supply payment.. Then redo only the first step that made the reasoning diverge, keeping units, direction, and model conditions visible.
Confirm current course details in the official Cambridge International syllabus for the 2026-2028 administration.
Where to go next
Return to the Cambridge International AS & A Level Economics (9708) to see every unit and plan your revision.