Government Intervention Methods — Topic Master Brief

#Pearson Edexcel IAL Economics WEC11/01

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#PROBABILITY: 🔴 HIGH — Every series contains tax, subsidy, or price control

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#SPEC COVERAGE — 1.3.6

Methods of intervention:

• Indirect taxation (ad valorem / specific)
• Subsidies
• Maximum prices (price ceiling — set BELOW equilibrium)
• Minimum prices (price floor / guaranteed price — set ABOVE equilibrium)
• Tradeable pollution permits
• Extension of property rights
• State provision
• Regulation
• Provision of information

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#INDIRECT TAX — THE KEY RULES

Specific tax: Fixed amount per unit → supply curve shifts LEFT by PARALLEL amount Jun 2022 examiner: "A £6 per kg tax requires a parallel shift in supply."

Ad valorem tax: Percentage of price → supply curve PIVOTS (becomes steeper, larger shift at higher prices)

Tax incidence split:

• Price elasticity of demand determines the consumer/producer split
• Inelastic demand: consumers bear larger incidence (price rises more)
• Elastic demand: producers bear larger incidence (price rises less, quantity falls more)

Diagram required for Level 3:

• S shifts LEFT from S to S+Tax
• New equilibrium: price rises Pe → P1, quantity falls Qe → Q1
• Consumer incidence: rectangle between Pe and P1 for quantity Q1
• Producer incidence: rectangle between Pnet received and Pe for quantity Q1
• Tax revenue: total rectangle = consumer + producer incidence

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#MAXIMUM PRICE (PRICE CEILING)

Set BELOW equilibrium price (Pe). If above Pe: no effect.

Diagram:

• Price ceiling at Pmax < Pe
• Quantity demanded extends to Qd (right of Qe)
• Quantity supplied contracts to Qs (left of Qe)
• Excess demand = shortage = Qd - Qs
• Consumer surplus: split — some gain (those who access at lower price), total CS may fall if shortage is severe

Effects:

• Consumers who access the good: benefit (lower price, higher CS)
• Consumers who cannot access: harmed (shortage)
• Producers: harmed (lower revenue, lower PS)
• Black market risk: unmet demand → black market price above even the original Pe

Confirmed context: Housing maximum rent (Jun 2021); food price ceiling (Philippines rice — Jun 2020)

Evaluation condition: "Maximum price succeeds only if enforcement prevents black market activity AND supply does not deteriorate to the point where the shortage eliminates the consumer welfare gain."

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#MINIMUM PRICE (PRICE FLOOR / GUARANTEED PRICE)

Set ABOVE equilibrium price (Pe). If below Pe: no effect.

Diagram:

• Minimum price at Pmin > Pe
• Quantity supplied extends to Qs (right of Qe)
• Quantity demanded contracts to Qd (left of Qe)
• Excess supply = surplus = Qs - Qd
• Government must PURCHASE the surplus to maintain the minimum price (fiscal cost)

Effects:

• Producers who sell: benefit (higher revenue, higher PS)
• Consumers: harmed (higher price, lower CS)
• Government: bears cost of purchasing surplus (fiscal burden)
• Storage costs: purchased surplus must be stored (additional cost)

Confirmed context: Philippines rice minimum price (Jun 2020); agricultural commodity markets; Scotland minimum alcohol price (proposed)

Evaluation condition: "Minimum price supports producer income only if demand for the good is price-inelastic — elastic demand generates a large surplus that exceeds the government's fiscal capacity to purchase."

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#SUBSIDIES — QUICK REFERENCE

Supply shifts RIGHT → price falls Pe → P1 → quantity rises Qe → Q1

Consumer incidence: price falls from Pe to P1 (consumer benefit) Producer incidence: receives P2 = P1 + subsidy per unit (producer benefit) Government cost: (P2 − P1) × Q1 = total subsidy spending

From Jun 2024 mark scheme (BEB subsidy €400):

• "Consumer surplus increases from PeEF to P1CF"
• "Producer surplus increases from PeEG to P1CH"
• "Government spending ACP1P2"

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#TWO DEPLOYABLE CHAINS

#CHAIN 1 — MAXIMUM PRICE ON HOUSING

Stage 1: A maximum price (rent ceiling) set below the free market equilibrium rent Pe prevents landlords from charging above Pmax, reducing the incentive to supply housing and extending tenant demand.

Stage 2: London's average private rent averaging £2,200/month — substantially above many households' ability to pay — reflects a housing market where free market price allocation excludes lower-income households from proximity to employment centres.

Stage 3: At Pmax < Pe, quantity demanded extends (Qd > Qe) as lower price makes housing accessible to more households, while quantity supplied contracts (Qs < Qe) as landlords reduce supply at the lower controlled price — creating a shortage of Qd - Qs.

Stage 4: The housing shortage means many lower-income households who cannot access housing at Pmax must either accept worse accommodation quality (landlords reduce maintenance at lower revenues), commute from cheaper areas (productivity loss), or enter the black market at prices exceeding the original Pe — the intended welfare benefit for tenants fails for those who cannot access the limited supply.

Stage 5: This welfare outcome holds only if the price ceiling is strictly enforced and supply does not deteriorate — if landlords exit the market (converting to owner-occupation or commercial use), the shortage deepens over time, eventually leaving lower-income households worse off than under the free market.

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#CHAIN 2 — MINIMUM PRICE ON AGRICULTURAL COMMODITY

Stage 1: A guaranteed minimum price set above the free market equilibrium raises the price received by producers above Pe, extending their quantity supplied while contracting consumer demand — generating a surplus that the government must purchase to maintain the floor price.

Stage 2: The Philippines rice minimum price (Jun 2020 extract) guaranteed farmers a floor price above the market clearing level, providing income stability for smallholder farmers facing volatile market prices — but generating surplus rice stocks requiring government storage and disposal.

Stage 3: At Pmin > Pe, quantity supplied extends to Qs as farmers expand cultivation at the guaranteed higher price, while quantity demanded contracts to Qd as consumers face higher prices — the surplus (Qs - Qd) must be purchased by government at the guaranteed price to prevent the floor from collapsing.

Stage 4: Smallholder farmers benefit (higher, more stable incomes reduce poverty risk), but consumers face higher food prices (potentially harming urban poor who spend a high proportion of income on rice), while government fiscal costs of purchasing, storing, and disposing of surpluses impose an ongoing burden that may crowd out other public expenditure.

Stage 5: The minimum price benefits farmers only if demand is sufficiently price-inelastic — if elastic, the quantity contraction on the consumer side generates a large, expensive surplus that eventually becomes fiscally unsustainable.

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#EVALUATION MOVES — ALL INTERVENTIONS

For indirect tax:

• Regressive: lower-income households bear larger incidence share of tax on necessities
• Inelastic demand: quantity barely falls despite price rise → minimal externality correction
• Tax set below MEC: correction partial only
• Revenue hypothecation: only corrective if tax revenue funds externality remediation

For subsidy:

• May benefit wrong group: EV subsidies predominantly benefit high-income buyers
• Opportunity cost: subsidy spending foregoes alternative uses (healthcare, education)
• Overconsumption risk: if too large, consumption overshoots social optimum

For maximum price:

• Black market emergence: enforcement failure → prices above original Pe
• Supply deterioration: landlords exit → quality falls → long-run housing shortage worsens
• Allocation problem: shortage requires queuing/rationing → non-price allocation may be less efficient

For minimum price:

• Surplus disposal cost: storage, export subsidies, destruction
• Consumer harm: higher prices hit poor urban households hardest
• Market distortion: surplus may need dumping in international markets → harm to other countries' farmers

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#DEFINE TERMS — KEY INTERVENTIONS

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