How does an indirect tax correct market failure?

An indirect tax raises the cost of production, shifting the supply curve left. This increases the market price and reduces the quantity consumed, moving output closer to the socially optimal level. The tax internalises the external cost by making the price reflect the true social cost of the good.

What are the limitations of indirect taxes as a government intervention?

Indirect taxes may be ineffective if demand is price inelastic, as consumption barely falls. They are regressive — low-income consumers pay a higher proportion of their income. Setting the correct tax rate is difficult due to information failure about the exact size of the externality. Taxes may also encourage black market activity.

Examine how the imposition of an indirect tax on sugary drinks could reduce market failure.

Sugary drinks can be classified as a demerit good — a good that is over-consumed because consumers underestimate the long-term health costs and because consumption generates negative externalities (e.g. increased burden on the NHS from obesity-related illness). K An indirect tax is a government-imposed levy on producers that raises the cost of production. K The UK introduced the Soft Drinks Industry Levy in 2018 as an example of this approach. A The tax shifts the supply curve leftward (from S to S+tax), raising the market price and reducing the equilibrium quantity consumed. An By increasing the private cost, the tax effectively internalises the external cost — making the market price closer to the true social cost of consumption. An This moves output from the free-market quantity (Qm) toward the socially optimal quantity (Qopt) , reducing the welfare loss (deadweight loss) caused by over-consumption. D However, the effectiveness of the tax depends on the price elasticity of demand for sugary drinks. An If demand is price inelastic — for example, among habitual consumers or those with few perceived substitutes — the reduction in quantity consumed will be small, and the tax will primarily raise revenue rather than change behaviour. An Conversely, the UK sugar levy has been credited with encouraging manufacturers to reformulate products with less sugar, reducing consumption even without large price increases — an outcome that extends the policy's impact beyond the simple price mechanism. A

Explain how an indirect tax can be used to correct a negative externality.

An indirect tax is a tax levied on the sale of goods or services, paid by producers but often passed on to consumers through higher prices. K A negative externality occurs when production or consumption imposes costs on third parties — meaning the social cost exceeds the private cost. K A government can set an indirect tax equal to the external cost per unit. This forces producers to internalise the externality — their private cost now includes the external cost, raising the supply curve to align with the marginal social cost. A Output falls from the free market level to the socially optimal level, and the welfare loss is eliminated. For example, the UK's landfill tax raises the cost of sending waste to landfill, encouraging recycling and reducing environmental damage. A

WEC11 8-mark examine question: Government Intervention (Unit 1) model answers | Edexcel IAL Economics

Revvy LearnEdexcel International A-LevelEconomics / Model answersOpen the app

Economics · WEC11 · Unit 1 · 1.3.6

Exam questions

Every question here carries a tariff that exists in IAL Economics. Open the mark scheme before the model answer and you will see what the examiner is paid to look for.

Examine8 marksAO1 · AO2 · AO3 · AO411 min
Examine how the imposition of an indirect tax on sugary drinks could reduce market failure.
Mark scheme
Examine (8)
Appendix 6: Requires knowledge, understanding, application, analysis and evaluation. Requires an explanation which includes a chain of reasoning, and diagrams where appropriate. Focuses on depth rather than breadth. Any relevant data provided needs to be interpreted. There should be a brief assessment of the arguments/factors/evidence.
Level 1 — 1–2 marks
Isolated knowledge and understanding. No application to the context and no chain of reasoning.
Level 2 — 3–4 marks
Knowledge applied to the context. A chain of reasoning is begun but not carried through; any data given is described rather than interpreted.
Level 3 — 5–6 marks
A developed chain of reasoning in context, with a diagram where one is appropriate. Depth rather than breadth; data interpreted. Assessment is implied rather than made.
Level 4 — 7–8 marks
A developed chain of reasoning in context AND a brief assessment of the arguments, factors or evidence — the clause that separates Examine from Analyse.
Indicative content
Knowledge: definition of indirect tax and/or negative externality / demerit good. Application: mechanism of tax on sugary drinks (raises price, internalises external cost). Analysis: developed chain through to reduced consumption, welfare gain, potential limitations.
Model answer — 7–8 / 8
What the marks in the margin meanKKnowledgeAApplicationAnAnalysis chainDDiagram ref.
Para 1
Sugary drinks can be classified as a demerit good — a good that is over-consumed because consumers underestimate the long-term health costs and because consumption generates negative externalities (e.g. increased burden on the NHS from obesity-related illness). K An indirect tax is a government-imposed levy on producers that raises the cost of production. K The UK introduced the Soft Drinks Industry Levy in 2018 as an example of this approach. A
Para 2
The tax shifts the supply curve leftward (from S to S+tax), raising the market price and reducing the equilibrium quantity consumed. An By increasing the private cost, the tax effectively internalises the external cost — making the market price closer to the true social cost of consumption. An This moves output from the free-market quantity (Qm) toward the socially optimal quantity (Qopt), reducing the welfare loss (deadweight loss) caused by over-consumption. D
Para 3
However, the effectiveness of the tax depends on the price elasticity of demand for sugary drinks. An If demand is price inelastic — for example, among habitual consumers or those with few perceived substitutes — the reduction in quantity consumed will be small, and the tax will primarily raise revenue rather than change behaviour. An Conversely, the UK sugar levy has been credited with encouraging manufacturers to reformulate products with less sugar, reducing consumption even without large price increases — an outcome that extends the policy's impact beyond the simple price mechanism. A
Examiner commentary
A developed chain: tax → supply shifts left → price rises → quantity falls → welfare loss narrows, applied to the Soft Drinks Industry Levy, with the tax wedge available for the diagram credit. Level 4 is earned in paragraph 3, where the answer does not leave the tax working: the outcome is made conditional on PED, the inelastic case in which the levy raises revenue rather than changing behaviour is stated, and reformulation is set against it. That is the brief assessment the command requires.
Why this loses marks — a mid-band attempt at the same question
Not a real script, and not written for this panel. It is 2 of 3 paragraphs of the model answer above, with “Para 3” removed. Nothing is rewritten. Open the model answer above and the difference is exactly the paragraphs named here.
What the marks in the margin meanKKnowledgeAApplicationAnAnalysis chainDDiagram ref.
Para 1
Sugary drinks can be classified as a demerit good — a good that is over-consumed because consumers underestimate the long-term health costs and because consumption generates negative externalities (e.g. increased burden on the NHS from obesity-related illness). K An indirect tax is a government-imposed levy on producers that raises the cost of production. K The UK introduced the Soft Drinks Industry Levy in 2018 as an example of this approach. A
Para 2
The tax shifts the supply curve leftward (from S to S+tax), raising the market price and reducing the equilibrium quantity consumed. An By increasing the private cost, the tax effectively internalises the external cost — making the market price closer to the true social cost of consumption. An This moves output from the free-market quantity (Qm) toward the socially optimal quantity (Qopt), reducing the welfare loss (deadweight loss) caused by over-consumption. D
The band this attempt cannot reach
Level 4 — 7–8 marks
A developed chain of reasoning in context AND a brief assessment of the arguments, factors or evidence — the clause that separates Examine from Analyse.
Where it tops out instead
Level 3 — 5–6 marks
A developed chain of reasoning in context, with a diagram where one is appropriate. Depth rather than breadth; data interpreted. Assessment is implied rather than made.
No mark is put on this attempt. The full answer above is marked 7–8 / 8 by its own commentary; what a truncated version scores depends on the script, and inventing a number for it would be the kind of false precision this page exists to avoid.
Explain4 marksAO1 · AO25 min
Explain how an indirect tax can be used to correct a negative externality.
Mark scheme
1–2 marks
Knowledge: definition of indirect tax and/or negative externality
3–4 marks
Application: tax internalises external cost, raises private cost to social cost level
Model answer — 4 / 4
What the marks in the margin meanKKnowledge/DefinitionAApplication
An indirect tax is a tax levied on the sale of goods or services, paid by producers but often passed on to consumers through higher prices. K A negative externality occurs when production or consumption imposes costs on third parties — meaning the social cost exceeds the private cost. K

A government can set an indirect tax equal to the external cost per unit. This forces producers to internalise the externality — their private cost now includes the external cost, raising the supply curve to align with the marginal social cost. A Output falls from the free market level to the socially optimal level, and the welfare loss is eliminated. For example, the UK's landfill tax raises the cost of sending waste to landfill, encouraging recycling and reducing environmental damage. A
Examiner commentary
Precise definitions followed by clear mechanism (tax = external cost, internalise, output falls to social optimum). The landfill tax example provides concrete application. Avoid saying "the government taxes the externality" — instead say "the tax equals the external cost per unit."

Open Government Intervention in the Revvy Learn app

Government Intervention (Unit 1) — Exam Questions & Model Answers

Exam questions

Para 1

Para 2

Para 3

Para 1

Para 2

The band this attempt cannot reach

Where it tops out instead