Changing Market Conditions (Cambridge (CIE) O Level Economics)

Revision Note

Steve Vorster

Expertise

Economics & Business Subject Lead

Causes and Consequences of Price Changes

  • Real world markets are constantly changing and are referred to as dynamic markets

  • Market equilibrium can change every few minutes in some markets (e.g. stocks and shares), or every few weeks or months in others (e.g Clothing)

  •  Any change to a condition of demand or supply will temporarily create disequilibrium and market forces will then seek to clear the excess demand or supply

Real world example: changes to demand that increase price

  • During lock downs associated with the Covid-19 pandemic, furniture retailers experienced unexpectedly high demand for their products (especially desks and sofas)

Supply and demand graph for desks shows supply curve (S), initial demand curve (D1), shifted demand curve (D2). Price rises from P1 to P2; quantity from Q1 to Q2.
Diagram showing an increase in demand for desks due to a temporary change in tastes/fashions

Diagram analysis

  • Due to the Covid mandated change of working from home, consumers experienced a temporary change in taste as they sought to set up comfortable home offices

    • This led to an increase in demand for desks from D1→D

  • At the original market clearing price of P1, a condition of excess demand now exists

    • The demand for desks is greater than the supply 

  • In response, suppliers raise prices

    • This causes a contraction of demand and an extension of supply leading to a new market equilibrium at P2Q2

    • Both the equilibrium price (P2) and the equilibrium quantity (Q2) are higher than before

    • The excess demand in the market has been cleared

Exam Tip

Be systematic in thinking through the order of changes in market conditions. e.g. an increase in demand (shift in demand) will cause a rise in price. The higher price will cause an extension of supply (not a shift of supply)

Real world example: changes to supply that increase price

  • In September 2022, Hurricane Fiona destroyed much of Puerto Rico's crop of plantains (a necessity in the diet of local people)

Diagram showing a decrease in supply of plantains in Puerto Rico due to a supply shock caused by Hurricane Fiona
Diagram showing a decrease in supply of plantains in Puerto Rico due to a supply shock caused by Hurricane Fiona

Diagram analysis

  • Due to Hurricane Fiona, Puerto Rico is experiencing a supply shock in its plantain market

    • This causes a decrease in supply of S1→S

  • At the original market clearing price of P1, a condition of excess demand now exists (shortage)

    • The demand for plantain is greater than the supply 

  • In response, sellers in Puerto Rico raise prices

    • This causes a contraction of demand and an extension of supply leading to a new market equilibrium at P2Q2

    • The equilibrium price (P2) is higher and the equilibrium quantity (Q2) is lower than before

    • The excess demand in the market has been cleared

Real world example: changes to demand that decrease price

  • Demand for lobsters in Maine, USA has been falling steadily in recent months

  • This has resulted in a price fall from $12.35 per pound on April 1st to $9.35 per pound on May 1st

Diagram showing a decrease in demand for lobsters due to a decrease in real income
Diagram showing a decrease in demand for lobsters due to a decrease in real income

Diagram analysis

  • In recent months, the USA has been experiencing an increasing rate of inflation

    • Inflation lowers the purchasing power of money in a consumer's pocket and, therefore, effectively reduces their real income

    • With reduced real income, fewer luxuries are consumed

    • This led to a decrease in demand for lobsters from D1→D

  • At the original market clearing price of P1, a condition of excess supply now exists

    • The demand for lobsters is less than the supply 

  • In response, suppliers gradually reduce prices

    • This causes a contraction of supply and an extension of demand, leading to a new market equilibrium at P2Q2

    • Both the equilibrium price (P2) and the equilibrium quantity (Q2) are lower than before

    • The excess supply in the market has been cleared

Real world example: changes to supply that decrease price

  • In order to help meet their climate targets and lower energy costs for households, the EU is providing subsidies for solar panels 

Diagram showing an increase in supply of solar panels in the EU due to a per unit subsidy
Diagram showing an increase in supply of solar panels in the EU due to a per unit subsidy

Diagram analysis

  • To help meet its climate change targets and lower household energy bills, the EU has provided a subsidy to solar panel retailers

    • This causes an increase in supply of S1→S

  • At the original market clearing price of P1, a condition of excess supply now exists (surplus)

    • The supply of solar panels is greater than the demand 

  • In response, sellers in the EU lower prices

    • This causes an extension of demand and a contraction of supply, leading to a new market equilibrium at P2Q2

    • The equilibrium price (P2) is lower and the equilibrium quantity (Q2) is higher than before

    • The excess supply in the market has been cleared

Exam Tip

MCQ frequently requires you to identify the consequences of dynamic changes in markets, e.g. the new equilibrium point after a change in the market). Memorise the conditions of demand and supply; by doing so, you will save valuable thinking time in the exam.

In structured questions, explaining the steps in the dynamic change is often referred to as analysis and students frequently leave out some steps in the explanation

Here is a systematic process to help build your explanation:

Step 1: From the scenario, identify if the change in condition is on the demand side or supply side

Step2: State which way the demand or supply curve moves and use notation, e.g. S1→S2

Step 3: State the disequilibrium that now exists at the original market price (excess demand or excess supply)

Step 4: State if sellers raise or lower prices to clear the disequilibrium

Step 5: Explain the relevant contraction and extension that occur on the demand and supply curves due to the change in price

Step 6: State the new market equilibrium points e.g. P2Q2

Step 7: Explain the market outcome (is the new price/quantity higher/lower than the original?)

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Steve Vorster

Author: Steve Vorster

Steve has taught A Level, GCSE, IGCSE Business and Economics - as well as IBDP Economics and Business Management. He is an IBDP Examiner and IGCSE textbook author. His students regularly achieve 90-100% in their final exams. Steve has been the Assistant Head of Sixth Form for a school in Devon, and Head of Economics at the world's largest International school in Singapore. He loves to create resources which speed up student learning and are easily accessible by all.