Beefed-up burgernomics
A gourmet version of the Big Mac index suggests that
the yuan is not that undervalued
Ketchup growth
Some find burgernomics hard to swallow. Burgers cannot easily be traded across borders, and prices are distorted by big differences in the cost of non-traded local inputs such as rent and workers’ wages. The Big Mac index suggests that most emerging-market currencies are significantly undervalued, for instance (Brazil and Argentina are the big exceptions). But you would expect average prices to be cheaper in poor countries than in rich ones because labour costs are lower. This is the basis of the so-called “Balassa-Samuelson effect”. Rich countries have much higher productivity and hence higher wages in the traded-goods sector than poor countries do. Because firms compete for workers, this also pushes up wages in non-tradable goods and services, where rich countries’ productivity advantage is smaller. So average prices are cheaper in poor countries. The top chart shows a strong positive relationship between the dollar price of a Big Mac and GDP per person
China’s average income is only one-tenth of that in America so economic theory would suggest that its exchange rate should be below its long-run PPP (ie, therate that would leave a burger costing the same in the two countries). PPP signals where exchange rates should be heading in the long run, as China gets richer, but it says little about today’s equilibrium rate. However, the relationship between prices and GDP per person can perhaps be used to estimate the current fair value of a currency. The top chart shows the “line of best fit” between Big Mac prices and GDP per person for 48 countries. The difference between the price predicted by the red line for each country, given its income per head, and its actual price offers a better guide to currency under- and overvaluation than the PPP-based “raw” index.
This alternative recipe, with its adjustment for GDP per person, indicates that the Brazilian real is still badly overcooked, at more than 100% too dear (see lower chart). The euro is 36% overvalued against the dollar, and our beefed-up index also throws useful light on the uncompetitiveness of some economies within the euro area. Comparing burger prices in member countries, the adjusted Big Mac index shows that the “exchange rates” of Italy, Spain, Greece and Portugal are all significantly overvalued relative to that of Germany. As for China, the yuan is close to its fair value against the greenback on the adjusted measure, although both are undervalued against many other currencies.
Super-size jubilee
In trade-weighted terms our calculations suggest that the yuan is a modest 7% undervalued, hardly grounds for a trade war. That is less than previous estimates of a 20-25% undervaluation, based on models that calculate the appreciation in the yuan needed to reduce China’s current-account surplus to a manageable level of, say, 3% of GDP. Even this surplus-based method now points to a smaller yuan undervaluation than it used to because China’s surplus has shrunk. Several private-sector economists forecast that it could drop below 4%of GDP this year, down from nearly 11% in 2007. As its productivity rises overtime China must continue to allow its real exchange rate to rise (either through currency appreciation or through inflation), but our new burger barometer suggests that the yuan is not hugely undervalued today.
A quarter of a century after its first grilling, burgernomics is still far from perfect, but if adjusted for GDP per person it becomes tastier.
All the more reason to keep putting our money where our mouth is.
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