Beefed-up burgernomics

　　日益強大的漢堡經濟學

　　THE Big Mac index celebrates its 25th birthday this year. Invented by The Economist in 1986 asa lighthearted guide to whether currencies are at their correct level, it was never intended asa precise gauge of currency misalignment, merely a tool to make exchange-rate theory moredigestible. Yet the Big Mac index has become a global standard, included in several economictextbooks and the subject of at least 20 academic studies. American politicians have even citedthe index in their demands for a big appreciation of the Chinese yuan. With so many peopletaking the hamburger standard so seriously, it may be time to beef it up.

　　巨無霸指數已經誕生25年了。在1986年的一期經濟學人雜志中第一次出現，當初僅僅是為了讓人們更易理解匯率，隨意的作為一個衡量貨幣是否在正常水平的指標，人們從沒有指望它能作為一個估評貨幣的標準。然而如今巨無霸指標已經成為國際的一個標準，被數個經濟讀本引用還成為至少20個學術研究的課題。美國的政客們甚至借這一數字來要求中國人民幣的增值。鑒于人們如此看重漢堡指數，可能是時候去討論一下它的意義了。

　　Burgernomics is based on the theory of purchasing-power parity , the notion that in thelong run exchange rates should move towards the rate that would equalise the prices of anidentical basket of goods and services in any two countries. Theaverage price of a Big Mac in America is $4.07; in China it is only $2.27 at market exchangerates, 44% cheaper. In other words, the raw Big Mac index suggests that the yuan isundervalued by 44% against the dollar. In contrast, the currencies of Switzerland and Norwayappear to be overvalued by around 100%. The euro is overvalued by 21% against the dollar; sterling is slightly undervalued;the Japanese yen seems to be spot-on. For the first time, we have included India in our survey.McDonalds does not sell Big Macs there, so we have taken the price of a Maharaja Mac, madewith chicken instead of beef. Meat accounts for less than 10% of a burgers total cost, so this isunlikely to distort results hugely. It indicates that the rupee is 53% undervalued.

　　以購買力等價理論為基礎，漢堡經濟旨在表示任意兩個國家，長期以來保持的匯率應該趨于使人們消費在同樣的商品或服務的金錢持平。在美國巨無霸的價格平均為每個$4.07，而在中國經市場匯率計算僅為$2.27，便宜了 44%。換句話說，原始的巨無霸指數顯示人民幣較美元被低估了44%。另一方面瑞士和挪威的貨幣則約被高估了100%。歐元較美元高估了21%;英鎊低估了一點點，日元則和美元持平。這是我們第一次將印度囊括在調查的國家中，因為麥當勞并不在印度銷售巨無霸，于是我們選取印度版巨無霸來研究，漢堡里面夾的是雞肉而不是牛肉。但肉的價格占整個漢堡價格的比例小于10%，所以這也不會使結果產生太大偏差。結果顯示，盧比的匯率被低估了53%。

　　Ketchup growth

　　番茄醬增值

　　Some find burgernomics hard to swallow. Burgerscannot easily be traded across borders, and pricesare 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, forinstance . But you would expect average prices tobe cheaper in poor countries than in rich onesbecause 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-goodssector than poor countries do. Because firms compete for workers, this also pushes up wagesin 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 positiverelationship between the dollar price of a Big Mac and GDP per person

　　一些人覺得很難接受漢堡經濟。因為漢堡不易跨國交易，而且價格隨著當地非交易商品的成本，例如租金、員工薪資的不同也有偏差。打個比方，巨無霸指數表明，大多數新興市場國家的貨幣的匯率很大程度上被低估，。但你可能認為貧窮國家的平均價格比富有國家的低，是因為勞動力更廉價，其實這是巴拉薩薩繆爾森效應帶來的偏見。富國的生產率比貧國的生產率高出很多，所以在商品交易環節的薪值更高。 又因為公司之間會競爭雇傭員工，這也使得非交易商品和服務上花費的金錢水漲船高。 所以 貧國的平均價格要低一些。上圖顯示了一個巨無霸的美元價值和個人的GDP之間有很強的正比關系。

　　Chinas average income is only one-tenth of that in America so economic theory would suggestthat its exchange rate should be below its long-run PPP . PPP signals where exchange rates should be headingin the long run, as China gets richer, but it says little about todays equilibrium rate. However,the relationship between prices and GDP per person can perhaps be used to estimate thecurrent fair value of a currency. The top chart shows the line of best fit between Big Macprices and GDP per person for 48 countries. The difference between the price predicted by thered line for each country, given its income per head, and its actual price offers a better guide tocurrency under- and overvaluation than the PPP-based raw index.

　　中國的平均收入只有美國人的1/10， 所以根據經濟理論，匯率應該比PPP長期保持的值低PPP顯示的是長期交易活動中，在中國變富的情形下，匯率的值應該何去何從。但是它并沒提及均衡利率。不論如何，價格和個人GDP之間的關系也許能用來評估貨幣的現期公平價值。上圖顯示，48個國家巨無霸價格和人均GDP間的最佳狀態， 表示每個國家價格差距的紅線，再加上個人收入額以及實際價格， 就會比純粹基于PPP數據得出結論，更好的指示出貨幣是低估了還是高估了。

　　Thisalternativerecipe, withitsadjustmentfor GDP perperson,indicatesthat theBrazilian realis still badlyovercooked, at more than 100% too dear . The euro is 36% overvalued against the dollar,and our beefed-up index also throws useful light onthe uncompetitiveness of some economies within theeuro area. Comparing burger prices in membercountries, the adjusted Big Mac index shows that theexchange rates of Italy, Spain, Greece and Portugalare all significantly overvalued relative to that ofGermany. As for China, the yuan is close to its fairvalue against the greenback on the adjustedmeasure, although both are undervalued againstmany other currencies.

　　通過這個可供選擇的方法，包含了調整后的個人GDP的數據，可以看出巴西貨幣雷亞爾實在是被炒得過火了。比原料價值高出了100%。歐元較美元被高估了36%，由此可見我們的巨無霸指數也揭示出一些歐元區國家缺乏競爭力的現狀。比較成員國國家的漢堡價格，調整之后的巨無霸指數顯示與德國相比，意大利，西班牙，希臘和葡萄牙的匯率都被高估了。至于中國，在調整后的尺度下看，人民幣已經接近與美元的公平價值，盡管兩國的匯率和其他許多國家的貨幣匯率相比還是被低估的。

　　Super-size jubilee

　　巨型周年紀念

　　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 reduceChinas current-account surplus to a manageable level of, say, 3% of GDP. Even thissurplus-based method now points to a smaller yuan undervaluation than it used to becauseChinas surplus has shrunk. Several private-sector economists forecast that it could dropbelow 4% of GDP this year, down from nearly 11% in 2007. As its productivity rises over timeChina must continue to allow its real exchange rate to rise , but our new burger barometer suggests that the yuan isnot hugely undervalued today.

　　從貿易加權的角度來看，分析表明人民幣只被低估了7%，根本不能成為貿易戰的原因。根據模型分析得出，人民幣的增值應該將中國的活期儲蓄盈余減少至一個可以控制的水平，比如說30%。而就是這個以盈余為評判標準的方法，現在也指出，由于中國的盈余縮減了，人民幣的低估值也小了。一些私營企業的經濟學家預測，中國今年的GDP的增長幅度將從2007年11%下降至不到4%。因為生產率連年上升，中國必須持續提高自己的實際匯率，，無論怎樣，我們新一輪的漢堡測量表都顯示，人民幣元沒有被太多的低估。

　　A quarter of a century after its first grilling, burgernomics is still far from perfect, but ifadjusted for GDP per person it becomes tastier. All the more reason to keep putting ourmoney where our mouth is.

　　漢堡經濟自第一次問世已經過去25年，它仍有很多不足，不過與個人的GDP值調整后就合理多了。這也讓我們有更多的理由去干些實事了。

　　Beefed-up burgernomics

　　日益強大的漢堡經濟學

　　THE Big Mac index celebrates its 25th birthday this year. Invented by The Economist in 1986 asa lighthearted guide to whether currencies are at their correct level, it was never intended asa precise gauge of currency misalignment, merely a tool to make exchange-rate theory moredigestible. Yet the Big Mac index has become a global standard, included in several economictextbooks and the subject of at least 20 academic studies. American politicians have even citedthe index in their demands for a big appreciation of the Chinese yuan. With so many peopletaking the hamburger standard so seriously, it may be time to beef it up.

　　巨無霸指數已經誕生25年了。在1986年的一期經濟學人雜志中第一次出現，當初僅僅是為了讓人們更易理解匯率，隨意的作為一個衡量貨幣是否在正常水平的指標，人們從沒有指望它能作為一個估評貨幣的標準。然而如今巨無霸指標已經成為國際的一個標準，被數個經濟讀本引用還成為至少20個學術研究的課題。美國的政客們甚至借這一數字來要求中國人民幣的增值。鑒于人們如此看重漢堡指數，可能是時候去討論一下它的意義了。

　　Burgernomics is based on the theory of purchasing-power parity , the notion that in thelong run exchange rates should move towards the rate that would equalise the prices of anidentical basket of goods and services in any two countries. Theaverage price of a Big Mac in America is $4.07; in China it is only $2.27 at market exchangerates, 44% cheaper. In other words, the raw Big Mac index suggests that the yuan isundervalued by 44% against the dollar. In contrast, the currencies of Switzerland and Norwayappear to be overvalued by around 100%. The euro is overvalued by 21% against the dollar; sterling is slightly undervalued;the Japanese yen seems to be spot-on. For the first time, we have included India in our survey.McDonalds does not sell Big Macs there, so we have taken the price of a Maharaja Mac, madewith chicken instead of beef. Meat accounts for less than 10% of a burgers total cost, so this isunlikely to distort results hugely. It indicates that the rupee is 53% undervalued.

　　以購買力等價理論為基礎，漢堡經濟旨在表示任意兩個國家，長期以來保持的匯率應該趨于使人們消費在同樣的商品或服務的金錢持平。在美國巨無霸的價格平均為每個$4.07，而在中國經市場匯率計算僅為$2.27，便宜了 44%。換句話說，原始的巨無霸指數顯示人民幣較美元被低估了44%。另一方面瑞士和挪威的貨幣則約被高估了100%。歐元較美元高估了21%;英鎊低估了一點點，日元則和美元持平。這是我們第一次將印度囊括在調查的國家中，因為麥當勞并不在印度銷售巨無霸，于是我們選取印度版巨無霸來研究，漢堡里面夾的是雞肉而不是牛肉。但肉的價格占整個漢堡價格的比例小于10%，所以這也不會使結果產生太大偏差。結果顯示，盧比的匯率被低估了53%。

　　Ketchup growth

　　番茄醬增值

　　Some find burgernomics hard to swallow. Burgerscannot easily be traded across borders, and pricesare 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, forinstance . But you would expect average prices tobe cheaper in poor countries than in rich onesbecause 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-goodssector than poor countries do. Because firms compete for workers, this also pushes up wagesin 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 positiverelationship between the dollar price of a Big Mac and GDP per person

　　一些人覺得很難接受漢堡經濟。因為漢堡不易跨國交易，而且價格隨著當地非交易商品的成本，例如租金、員工薪資的不同也有偏差。打個比方，巨無霸指數表明，大多數新興市場國家的貨幣的匯率很大程度上被低估，。但你可能認為貧窮國家的平均價格比富有國家的低，是因為勞動力更廉價，其實這是巴拉薩薩繆爾森效應帶來的偏見。富國的生產率比貧國的生產率高出很多，所以在商品交易環節的薪值更高。 又因為公司之間會競爭雇傭員工，這也使得非交易商品和服務上花費的金錢水漲船高。 所以 貧國的平均價格要低一些。上圖顯示了一個巨無霸的美元價值和個人的GDP之間有很強的正比關系。

　　Chinas average income is only one-tenth of that in America so economic theory would suggestthat its exchange rate should be below its long-run PPP . PPP signals where exchange rates should be headingin the long run, as China gets richer, but it says little about todays equilibrium rate. However,the relationship between prices and GDP per person can perhaps be used to estimate thecurrent fair value of a currency. The top chart shows the line of best fit between Big Macprices and GDP per person for 48 countries. The difference between the price predicted by thered line for each country, given its income per head, and its actual price offers a better guide tocurrency under- and overvaluation than the PPP-based raw index.

　　中國的平均收入只有美國人的1/10， 所以根據經濟理論，匯率應該比PPP長期保持的值低PPP顯示的是長期交易活動中，在中國變富的情形下，匯率的值應該何去何從。但是它并沒提及均衡利率。不論如何，價格和個人GDP之間的關系也許能用來評估貨幣的現期公平價值。上圖顯示，48個國家巨無霸價格和人均GDP間的最佳狀態， 表示每個國家價格差距的紅線，再加上個人收入額以及實際價格， 就會比純粹基于PPP數據得出結論，更好的指示出貨幣是低估了還是高估了。

　　Thisalternativerecipe, withitsadjustmentfor GDP perperson,indicatesthat theBrazilian realis still badlyovercooked, at more than 100% too dear . The euro is 36% overvalued against the dollar,and our beefed-up index also throws useful light onthe uncompetitiveness of some economies within theeuro area. Comparing burger prices in membercountries, the adjusted Big Mac index shows that theexchange rates of Italy, Spain, Greece and Portugalare all significantly overvalued relative to that ofGermany. As for China, the yuan is close to its fairvalue against the greenback on the adjustedmeasure, although both are undervalued againstmany other currencies.

　　通過這個可供選擇的方法，包含了調整后的個人GDP的數據，可以看出巴西貨幣雷亞爾實在是被炒得過火了。比原料價值高出了100%。歐元較美元被高估了36%，由此可見我們的巨無霸指數也揭示出一些歐元區國家缺乏競爭力的現狀。比較成員國國家的漢堡價格，調整之后的巨無霸指數顯示與德國相比，意大利，西班牙，希臘和葡萄牙的匯率都被高估了。至于中國，在調整后的尺度下看，人民幣已經接近與美元的公平價值，盡管兩國的匯率和其他許多國家的貨幣匯率相比還是被低估的。

　　Super-size jubilee

　　巨型周年紀念

　　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 reduceChinas current-account surplus to a manageable level of, say, 3% of GDP. Even thissurplus-based method now points to a smaller yuan undervaluation than it used to becauseChinas surplus has shrunk. Several private-sector economists forecast that it could dropbelow 4% of GDP this year, down from nearly 11% in 2007. As its productivity rises over timeChina must continue to allow its real exchange rate to rise , but our new burger barometer suggests that the yuan isnot hugely undervalued today.

　　從貿易加權的角度來看，分析表明人民幣只被低估了7%，根本不能成為貿易戰的原因。根據模型分析得出，人民幣的增值應該將中國的活期儲蓄盈余減少至一個可以控制的水平，比如說30%。而就是這個以盈余為評判標準的方法，現在也指出，由于中國的盈余縮減了，人民幣的低估值也小了。一些私營企業的經濟學家預測，中國今年的GDP的增長幅度將從2007年11%下降至不到4%。因為生產率連年上升，中國必須持續提高自己的實際匯率，，無論怎樣，我們新一輪的漢堡測量表都顯示，人民幣元沒有被太多的低估。

　　A quarter of a century after its first grilling, burgernomics is still far from perfect, but ifadjusted for GDP per person it becomes tastier. All the more reason to keep putting ourmoney where our mouth is.

　　漢堡經濟自第一次問世已經過去25年，它仍有很多不足，不過與個人的GDP值調整后就合理多了。這也讓我們有更多的理由去干些實事了。