Economics • Government Intervention

Market Intervention & Elasticity

Market equilibrium and government intervention

0 20 40 60 80 100 0 20 40 60 80 100 Quantity Price ($) Pe Qe D S1
  • CS Consumer surplus
  • PS Producer surplus
  • Gov Revenue / spending
  • DWL Deadweight loss

Examples

Government intervention

Choose a tax, a subsidy or a price control in the title bar.

The market

Economic indicators

Price paid by consumers (Pc) Consumer $0
Price received by producers (Pp) Producer $0
Quantity traded (Q) Output 0
Consumer surplus (CS) Welfare $0
Producer surplus (PS) Welfare $0

Market Intervention & Elasticity — Explanation

Choose how the government intervenes in the title bar, then use the sliders to see how the price elasticity of demand and supply changes the result. Tick Show welfare areas to shade consumer surplus, producer surplus, the government's revenue or spending, and the deadweight loss.

A maximum price set above the equilibrium, or a minimum price set below it, has no effect: the market price is already allowed.

Deadweight loss is the welfare lost because the quantity traded is no longer the free-market quantity Qe: the units that were worth more to consumers than they cost to make, but aren't traded (or, with a subsidy, units that cost more than they're worth). With price controls it assumes the units traded go to the consumers who value them most (a maximum price) and that the government doesn't buy up the surplus (a minimum price).

The examples animate each change from the free market, with the old equilibrium (e0) greyed.

Cambridge International AS & A Level Economics (9708): price elasticity of demand and supply, and government intervention in markets (maximum and minimum prices, indirect taxes and subsidies, and their incidence).

Where this fits

  • AP: AP Microeconomics
  • AQA: AQA A Level Economics (7136)
  • Cambridge: Cambridge IGCSE Economics (0455); Cambridge A Level Economics (9708); Cambridge AS Level Economics (9708) Goes beyond Cambridge IGCSE Economics (0455): Tax incidence, consumer and producer surplus and deadweight loss aren't in 0455.
  • IB: IB Economics HL; IB Economics SL
  • NCEA Level 2 Economics: 91228 Analyse a contemporary economic issue of special interest using economic concepts and models
  • NCEA Level 3 Economics: 91399 Demonstrate understanding of the efficiency of market equilibrium; 91401 Demonstrate understanding of micro-economic concepts
  • Pearson Edexcel International: Edexcel International GCSE Economics (4EC1); Edexcel International A Level Economics Goes beyond Edexcel International GCSE Economics (4EC1): Maximum and minimum prices and the welfare areas (surplus, deadweight loss) aren't in 4EC1.
  • USDP: USDP Economics Goes beyond USDP Economics: Tax incidence and the welfare areas go beyond a typical high-school course.

Market Intervention & Elasticity — Key Terms

Key concepts in English, with te reo Māori, Chinese (Simplified) and Korean.

EnglishTe reo Māori中文(简体)한국어What it means on this page
Price Ceiling (Maximum Price)no attested term最高限价 (zuìgāo xiànjià)최고가격제 (choego gagyeokje)A legal maximum price set below the market equilibrium price, often creating a shortage.
Price Floor (Minimum Price)no attested term最低限价 (zuìdī xiànjià)최저가격제 (choejeo gagyeokje)A legal minimum price set above the market equilibrium price, often creating a surplus.
Price Elasticity of Demand (PED)no attested term需求价格弹性 (xūqiú jiàgé tánxìng)수요의 가격탄력성 (suyoui gagyeok tallyeokseong)A measure of how responsive quantity demanded is to a change in price.
Price Elasticity of Supply (PES)no attested term供给价格弹性 (gōngjǐ jiàgé tánxìng)공급의 가격탄력성 (gonggeubui gagyeok tallyeokseong)A measure of how responsive quantity supplied is to a change in price.
Excess Demand (Shortage)popono tuhene需求过剩 (xūqiú guòshèng)초과수요 (chogwa suyo)The amount by which quantity demanded exceeds quantity supplied at a given price, typically below equilibrium.
Excess Supply (Surplus)whakaratonga tuhene供给过剩 (gōngjǐ guòshèng)초과공급 (chogwa gonggeub)The amount by which quantity supplied exceeds quantity demanded at a given price, typically above equilibrium.
Indirect Taxno attested term间接税 (jiànjiē shuì)간접세 (ganjeobse)A tax on spending, such as on a good or service, that is collected from the seller but can be passed on to the buyer.
Specific Taxno attested term从量税 (cóngliàng shuì)종량세 (jongnyangse)An indirect tax of a fixed amount on each unit sold, such as $2 a litre. It shifts the supply curve up by the same amount at every quantity, so S2 is parallel to S1.
Ad Valorem Taxno attested term从价税 (cóngjià shuì)종가세 (jonggase)An indirect tax charged as a percentage of the price, such as GST. It pivots the supply curve upwards, so the tax per unit grows as the price rises.
Subsidypūtea āwhina补贴 (bǔtiē)보조금 (bojogeum)A payment by government to a producer, used to lower costs and increase output of a good.
Incidence of Taxno attested term税收归宿 (shuìshōu guīsù)조세귀착 (jose gwichak)How the burden of a tax is shared between consumers and producers, depending on the relative elasticity of demand and supply.
Consumer Surplusno attested term消费者剩余 (xiāofèizhě shèngyú)소비자잉여 (sobija ingyeo)The difference between what consumers are willing to pay for a good and what they actually pay.
Producer Surplusno attested term生产者剩余 (shēngchǎnzhě shèngyú)생산자잉여 (saengsanja ingyeo)The difference between the price producers receive for a good and the minimum price they would be willing to accept.
Deadweight Welfare Lossno attested term福利无谓损失 (fúlì wúwèi sǔnshī)사회후생 손실 (sahoe husaeng sonsil)The consumer and producer surplus lost, and not gained by anyone else, when a tax, subsidy or price control moves the quantity traded away from the free-market equilibrium.
Black Marketno attested term黑市 (hēishì)암시장 (amsijang)An illegal market that arises when a price ceiling creates a shortage, where goods are sold above the legal maximum price.

On the te reo Māori column. Terms marked as gaps have no attested equivalent in the sources checked — Karaitiana Taiuru's Dictionary of Māori Computer and Social Media Terms, Paekupu, the Reserve Bank's te reo financial glossary, NZQA and Te Aka. No coinage is printed as though it were established; where a class needs one, commission it from Te Taura Whiri i te Reo Māori and credit the translator. Te reo Māori is not italicised and takes no plural "s".