Related Unit: IB Economics Unit 4.7 – Balance of Payments

Topic: The Marshall Lerner Condition and the J-Curve

Learning Goals/Objectives:

• For students to understand that the levels of price elasticity of demand for a country’s imports and exports determines whether a depreciation or devaluation of the country’s currency will move the nation’s balance of payments towards a surplus or a deficit.
• For students to understand the impact of time on the effect of a depreciation or devaluation of a nation’s currency on its balance of payments in the current account.
• For students to evaluate the argument that a country will always benefit from a weaker currency.

Success Indicators:

• Students will present their PowerPoint presentations of their exchange rate research, explaining how elasticity, exchange rates, and the balance of payments are related.
  
• Students will be able to outline their answers to three IB Economics examination questions relating to the Marshall Lerner Condition
  

Test of prior knowledge:

1. Define ‘price elasticity of demand’ and explain how it is measured.
2. With the use of examples, explain why some products have low price elasticity while others have a high elasticity. With the use of examples, explain why the price elasticity of demand for some goods changes over time
3. Explain how the depreciation of a country’s exchange rate might affect its current account balance.
   IS THIS ALWAYS THE CASE?
4. How might the PED for exports and imports influence the balance on the current account following a change in the value of a nation’s currency?

Process: Students should work in groups of four

• Each group chooses two countries
  • US and Canada
  • Switzerland and Great Britain
  • Euro area and Japan
  • Brazil and US
• Complete three pre-readings:
  • From BizEd:
    The Marshall Lerner Condition and The Economic Effects of a Devaluation
  • From Welker’s blog: The Marshall Lerner Condition and the J-Curve
    
• Using Yahoo Finance, research exchange rate data from the two countries two years ago up to today.
• Use Yahoo’s software to create two line graphs plotting the value of Country A’s currency against Country B’s, and Country B’s against Country A’s. For example:

The exchange rate of US dollars in Australia

The exchange rate of Australian dollars in the US:

• Finally, Create a PowerPoint presentation of your answers to the following questions. Include in the presentation the graph of the exchange rates created in the step above.

Of the four members of each group, two should prepare the section of the PowerPoint answering the following questions from the perspective of Country A and two from the perspective of Country B

Country A: ____________________ and ______________________

Country B: ____________________ and ______________________

Questions the PowerPoint should answer:

1. What is the Marshall Lerner Condition? Why is it important to consider the price elasticities of demand for exports and imports when examining the impact of a change in exchange rates on the current account balance?
   
2. Describe two periods of time from your line graph: One in which your country’s currency strengthened and one in which it weakened against the other country’s currency.
   
3. Using your knowledge of economics, explain TWO factors that may have caused the changes you have identified.
   
4. Given the changes identified, what would you predict would be happening to your country’s current account of the balance of payments over the three periods you specified above?
   
   1. Period 1: _______________________
      
   2. Period 2: _______________________
5. For both the periods of change, explain the impact of the change in exchange rates on the following:
   
   1. a firm that imports its raw materials from the other country
      
   2. a firm that exports its finished products to the other country
      
   3. consumers who buy imports from the other country
      
   4. a firm that produces good for the domestic market and competes with firms from the other country
      
6. Consider the impact of changes in the exchange rate on amount spent on imports and the revenue earned from exports (and thus, the current account balance). Assume the following for the three periods from your chart:
   
   1. Period 1: The price elasticity of demand for imports is 0.35 and the price elasticity of demand for exports is 0.55.
      
      1. Import spending will __________________
         
      2. Export revenue will __________________
         
      3. The current account will move towards DEFICIT or SURPLUS (identify which)
         
      4. Is the Marshall Lerner Condition met? Explain
         
   2. Period 2: The price elasticity of demand for imports is 0.5 and the price elasticity of demand for exports is 2.6.
      1. Import spending will __________________
      2. Export revenue will __________________
      3. The current account will move towards DEFICIT or SURPLUS (identify which)
      4. Is the Marshall Lerner Condition met? Explain
7. Think about the period in which your country’s currency weakened. Assume that the currency remains weak. How would the balance on the current account change over time following the depreciation of the country’s currency. Draw a J-Curve and explain its shape, referring to your country’s currency.
8. Look at the following article: ‘How Far Will the Dollar Fall?’ by Richard W. Rahn.
   1. Explain how the fall in the dollar might help to reduce the US trade deficit.
   2. Assess Dr Rahn’s argument that taxation and regulation are the principle causes of the potential for the limits to growth in the world economy.

You’re now prepared to consider the elasticity implications for balance of payments. Test your own understanding of the Marshall Lerner condition by answering the following IB questions:

1. With reference to the Marshall-Lerner condition, explain how the depreciation of a country’s exchange rate might affect its current account balance. (Total 10 marks)
2. An economy is currently experiencing a deficit on the current account of its balance of payments. The government is considering either allowing the exchange rate to fall or reducing aggregate demand. Evaluate the relative advantages and disadvantages of these two policies. (15 marks)
3. Explain how, in theory, balance of payments deficits and surpluses on current account are automatically adjusted under a system of flexible exchange rates. Illustrate your answer using supply and demand analysis. (Total 10 marks)

The above lesson was inspired by the Biz-Ed activity “International Trade: The Falling Dollar or Rising Pound?”

About the author: Jason Welker is a teacher at Zurich International School in Switzerland, where he teaches Advanced Placement and International Baccalaureate Economics. Jason was an international school student in Malaysia before studying economics at Seattle University then earning his Masters in Education. He calls Seattle and Northern Idaho home. In addition to maintaining an economics wiki and this blog for economics student and educators, Jason also gives presentations on using Web 2.0 tools in education at workshops and conferences around the world. His economics wiki won the 2007 "Best Educational Wiki" award from the "EduBlog Awards".

Related posts:

1. The Marshall-Lerner Condition, the J-curve, and the US trade deficit
2. Exchange rates and trade: a delicate balancing act, currently out of balance!
3. How do changing interest rates affect exchange rates? The example of the RMB
4. Exchange rates, currency manipulations, and the balance of trade
5. Another question from the Help Desk: Relative price levels as a determinant of exchange rates

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