Archive for the 'Currency' Category

Dec 12 2008

The Marshall-Lerner Condition, the J-curve, and the US trade deficit

For a video lesson on the Marshall Lerner Condition and the J-curve, click here: The Marshall-Lerner Condition (HL Only) | The Economics Classroom

Read the following article before reading the blog post below:
Managing Globalization » Business Blog » International Herald Tribune » Blog Archive » Here’s that silver lining, finally

In IB Economics we’ve been studying concepts relating to balance of trade and exchange rates. The Marshall-Lerner Condition and the J-curve are two concepts that explain the relationship between a the exchange rate for a nation’s currency and the country’s balance of trade. (click on the graph to see a larger version)

Common sense might indicate that if a country’s currency (let’s say the US dollar) depreciates relative to other currencies, then this should lead to an improvement in the country’s balance of trade (economists call this the current account). The reasoning goes as such: a weaker dollar means foreigners will have to give up less of their money in order to get one dollar’s worth of American output. At the same time, since the dollar is worth less in foreign currency, imports become more expensive, as Americans have to fork over more dollars for a certain amount of another country’s output; hence, imports should decrease.

Fewer imports and more exports means an improvement in the country’s balance of trade, right? Well, not necessarily. What matters is not whether a country is importing less and exporting more, rather, whether the increase in income from exports exceeds the decrease in expenditures on imports. Here is where the Marshall-Lerner Condition can be applied.

The M-L condition examines the price elasticities of demand for exports and imports of a particular country. Say the US experiences a depreciation of its currency (as it has over the last year or so). If foreigners’ demand for exports from America is relatively elastic, then a slightly weaker dollar should cause a dramatic increase in foreign demand for American output, causing export income in the US to rise dramatically. On the other hand, if American’s demand for imports is highly price elastic, then a slightly weaker dollar should likewise cause Americans’ demand for imports to decrease drastically, reducing greatly American’s expenditures on imports. If the combined elasticities of demand for exports and imports is elastic (i.e. the coefficient is greater than 1), then a depreciation of a nations currency will shift its current account towards surplus. This is the Marshall-Lerner Condition.

Marshall-Lerner Condition: If PEDx + PEDm > 1, then a depreciation or a devaluation of a nation’s currency will shift the the balance on its current account towards surplus.

So what if the Marshall Lerner Condition is not met? Demand for exports and imports may not always be so responsive to changes in exchange rates. Imagine a scenario where a weaker dollar does little to change foreign demand for America’s output. In this case income from exports may actually decline (in real terms, since the dollar is weaker) as the dollar depreciates. Likewise, if Americans’ demand for imports is highly inelastic, then more expensive imports will only minimally affect Americans’ demand for imported goods, in which case expenditures on imports may actually rise as they become more expensive. In this case, where the elasticities of demand for exports and imports are highly inelastic, a depreciation of the currency will actually worsen a trade deficit. Americans’ import expenditures will go up while export income from abroad will decline shifting the current account further into deficit.

In the article above, some data is presented that points to evidence that in the US today, the Marshall-Lerner Condition is in fact being met:

“Exports in the year through September are up by 12 percent from 2006, while the dollar’s trade-weighted exchange rate dropped by only 6 percent. That means foreigners may actually be spending more – even in their own currencies – on American products. It’s a support that the American economy, and in turn the global economy, can really use right now.

Of course, this process isn’t helping the trade deficit too much, No one, it seems, can change Americans’ taste for foreign products. But it does show, for all to see, that the risks of an open economy are at least somewhat balanced by the benefits.”

An increase in exports of 12% in response to a 6% weakening of the dollar indicates a price elasticity of demand coefficient for America’s exports of 2, meaning foreigners are highly responsive to cheaper US goods.

We can assume that Americans’ demand for imports is highly inelastic, as the article hints at when it says, “imports to the United States, including oil, are still rising in volume and value.” If a 6% weaker dollar leads to an increase in expenditures on imports, then demand must be less than one. In order for M-L Condition to be met, PEDx+PEDm must be greater than 1. Clearly, with a PEDx of 2, the condition is met, and a weaker dollar in leading to an improvement in America’s balance of trade with the rest of the world.

Discussion Questions:

    1. What is the J-curve effect? Based on the evidence from the article, where on the J-curve is the US right now?
    2. Is America experiencing an improvement in or a worsening of its current account deficit?
    3. What determinants of demand are fueling America’s ever-increasing expenditures on imports?
    4. What should happen to the elasticity of demand for imports if the dollar remains weak in the long-run? How will this affect America’s position on the J-curve?


119 responses so far

Dec 04 2008

Are you prepared for the new alternate currency?

Published by under Currency,Humor,Money

xkcd – A Webcomic – Alternate Currency

Alternate Currency

8 responses so far

Dec 03 2008

How the weak British Pound made my Himalayan ski fantasy a reality!

BBC NEWS | Business | Sterling rebounds from sharp fall

Americans, are you planning a vacation anytime soon? If so, why not visit LOVELY Great Britain! Why, you ask, would ANYONE want to visit the UK in during this wet, cold season? Well, here’s why I’m buying British this year:

I recently booked a Himalayan ski tour in Indian Kashmir organized by a British company. The price? 1400 GBP, which only three months ago was the equivalent of $2800 US! Today, with the newly weak British Pound, my ski trip to India will only cost me $2100*. In the span of just a few months, the dollar price of this amazing Himalayan ski adventure has fallen by $700! Naturally, Americans like myself now have an incentive to buy British!

POUND STERLING v UNITED STATES DOLLAR: December 2007 – December 2008


What has caused the slide of the Pound in recent months? Here’s the complicated answer:

“The environment of very weak sentiment regarding the domestic economic picture and potential rate cuts alongside equity volatility is keeping sterling very much on the defensive,” said Jeremy Stretch, strategist at Rabobank.

Strategists get paid lots of money to say stuff that 99% of people don’t understand the first time they read it. I get paid very little money to help those people better understand it, specifically, my students. Here’s what Mr. Stretch is trying to say:

A weak economy in Great Britain leads foreign investors to believe that the Bank of England may lower interest rates in the near future. Why would Britain’s central bank lower interest rates? Because lower interest rates create an incentive for consumers and businesses to take out loans from banks and spend money in the economy, which should create new jobs and help prevent a recession in the UK.

If the bank does lower interest rates, this puts “the sterling on the defensive”, in other words, leads to a weakening of the British Pound, as foreign investors looking to put their money where they can earn a decent return on it will be less likely to save in the UK when interest rates fall. “Equity volatility” is a fancy way of saying British stocks have been performing poorly, decreasing their attraction to foreign investors. When saving in British banks becomes less attractive due to expected interest rate cuts, and buying British stocks becomes risky due to their volatility, investors turn to the safest investment in the world, which is… can you guess? United States government bonds!

So how’s this all relate to exchange rates, you ask? Let’s leave this question for readers to answer and discuss in the comments:

Discussion Questions:

  1. How does the expected drop in British interest rates affect the demand for British pounds on foreign exchange markets? What does this do to the value of the pound?
  2. Why does the stability and safety of US government bonds lead to a strengthening of the dollar in times of global economic slowdowns?
  3. How has the recession in the United States further contributed to the weakening of the British pound?

*In fact, I’m too poor to take a ski trip to India this year, I will have to settle for the puny peaks here in the Swiss Alps!

20 responses so far

Jun 01 2008

Purchasing Power Parity – “for the inebriated masses” – the price of beer anywhere in the world

The theory of purchasing power parity (or PPP) holds that in the long run, the price of a particular basket of goods should adjust across countries and currencies to “cost” the same amount regardless of the currency the goods are denominated in. In other words, one dollar should buy the same amount of “stuff” in the US as it does in Mexico, China, the Netherlands or anywhere else in the world. If a dollar buys MORE in one of these countries once it’s been converted to the local currency, it implies that the local currency is undervalued and should adjust in the long run to achieve parity in the amount it can purchase in dollar terms.

One popular measure of purchasing power parity, devised by the folks at the Economist magazine’s intelligence unit, is the Big Mac Index, which measures the price of McDonald’s Big Macs in over 100 countries where they can be purchased. You can read more about this index here.

The Economist magazine recently reported on an new alternative to its own PPP index, “the Price of a Pint”:

Barflies around the world provide a useful service for their beer-drinking comrades at The prices of pints of lager are compared on the basis of anecdotal evidence from beer-drinkers around the world, so figures are regularly updated. There are some surprising results. Beer in Zambia and Burundi seems eye-wateringly expensive considering that they are among the world’s poorest countries. The French overseas départments of Guadeloupe and Martinique charge just about as much as in mainland France. Beer-loving America and Britain fall somewhere in the middle. Happily for sports fans at the Beijing Olympics, a pint in China is just $2.46.

I thought it might be useful to some of our graduating seniors planning their summer vacations or gap years. Pay close attention to the data in this table.


So, if cheap beer is a priority in your vacation decision, it looks like North Korea and Myanmar are ideal destinations. I must say, I am relieved to see that Switzerland, my own new home, is not in the top ten… but it is far from cheap.

The website will tell you the average price of a pint of beer in any country in the world, and then break it down to cities within each country. In Zurich, my soon to be home, a pint costs the equivalent of $6.57 US. Compared to my hometown of Seattle, Washington, where a pint goes for $3.25, that’s exactly double the price! Surprisingly, however, a pint of beer here in Shanghai goes for a shocking $5.15, more than double the Chinese average of $2.35.

Apparently, the price of beer has more to do with the local supply and demand than with relative exchange rates. Where the Big Mac Index offers a rather genuine approach to determining purchasing power parity (since the Big Mac is an identical product sold by the same restaurant facing similar costs in over 100 countries), a pint of beer is a bit more subjective a measure of PPP. Quality of beers clearly differ in locales as diverse as North Korea and Luxembourg, not to mention the incomes of beer drinkers, the number of domestic brewers, excise and value added taxes, consumers’ price elasticities of demand, and so on.

As summer vacation approaches, however, vacation planners may care to take into account the “Price of a Pint” index of purchasing power parity. Clearly, one’s dollars will go much further at bars in some places than others.

I know what you 18 year old American high school grads are thinking, “Mexico or Canada?” You’ll just have to follow the link to find out!

(Disclaimer: Mr. Welker is in no way encouraging his former students to travel to certain places based solely on the cheap price of beer there, merely to avoid places where beer is clearly out of their price range!)

11 responses so far

May 22 2008

Reflections on the weak dollar

I recently received an email from Sean Stoner, who writes a great blog, Maslow Forgot About Beer. I had previously commented on a post Sean wrote about McCain and Clinton’s proposed gas tax holiday, which is how he found my blog. Sean wanted to know my views on the weak dollar:


What do you believe is the most direct cause(s) of the weakening of the dollar? Is it the trade deficit and/or spending deficits along with increased borrowing overseas? Is it offshoring? Tax cuts? And how direct is the causality of this to oil and commodity prices?

Of course I’ll give you full credit in the post for educating me more on this subject. Thanks in advance !


Below is my reply. I am posting it here for posterity, and because I think it may include one possible explanation of the weak dollar within the grasp of IB and AP Econ students:

Hi Sean,

Keep in mind, I’m no expert here, only a high school economics teacher… but let me just share a few thoughts about one cause of the weak dollar.

I think something you’ve forgotten to mention in your email is the role that the mortgage crisis has had on the dollar. Much of the debt from the sub-prime mortgage market was held by overseas investors. As home foreclosures picked up late last year, confidence in these mortgage-backed securities plummeted and demand for these American assets fell, thus demand for dollars among foreign investors has fallen with it, depreciating the dollar.

I think the housing market is at the core of a lot of our woes right now. In my econ class we talk about the “wealth effect” of falling home prices on consumer spending. Besides disposable income, the main determinant of overall consumption in the economy is the level of “wealth” among households. Of course, Americans’ greatest source of wealth is their homes… and the reason home prices have fallen is a simple supply and demand story, which is within the grasps of anyone who knows how supply and demand interact to determine price in a marketplace.

Low interest rates during the late Greenspan era spurred a period of new home sales, which drove prices up, spurring a building frenzy which shifted supply out. As long as demand increased more rapidly than supply, the illusion that house prices would continually rise was believable, thus buyers could be convinced that an adjustable rate mortgage (ARM) was the perfect type of loan for them. But the rising prices were unsustainable, and when the Fed began increasing interest rates a few years ago, demand for new homes declined, right as inventory was at an all time high. Naturally, home prices began to stabilize then fall, and as the “adjustable” part of all those “sub-prime” ARMs kicked in, monthly payments became too much for some Americans to bear. In an attempt to liquidate their now unaffordable houses, millions of Americans put their homes for sale, while thousands began to default on their loans, both which combined to shift supply ever further outward, putting even more downward pressure on home prices.

The story continues from here: falling home prices mean less “wealth” which means less consumer spending which means less total output in the economy which means less demand for workers which means rising unemployment… aka, RECESSION! And that’s where we are today.

So, as you can see I think the housing market is at the core of our problems. The weak dollar too, as demand for American homeowners’ debt has declined among foreign investors. Now, in the face of a recession, the Fed has lowered interest rates once again to try and stimulate new spending and investment, further exacerbating the dollar’s decline, as lower returns in the US bond market divert investors out of dollars and into more secure investments, such as… you guessed it, OIL.

The falling dollar had encouraged investors to look for stable investments, such as commodities like oil, copper, coal, etc, driving demand and prices for these commodities up, contributing to the cost-push inflation that has accompanied America’s economics slowdown.

So yes, it’s all connected… rising unemployment, sluggish growth, rising price levels and falling real wages. At the core, however, is the housing market and the “irrational exuberance” that led to a speculative building and buying spree over the last six years: a bubble which began bursting late last year and continues to have a ripple effect across the economy.

Bush’s tax cuts and deficit spending just made this whole mess even worse. I did a blog post a while back about the trade deficit with China, budget deficits and the value of the dollar, you can read that here: “Excuse me China, could you lend us another billion?”

Okay, that’s all I’ve got for you today… I hope some of these observations are useful!

Best, Jason

3 responses so far

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