BIG MAC INDEX
Burgernomics is based on the theory of purchasing-power parity, the notion that a dollar should buy the same amount in all countries. Thus in the long run, the exchange rate between two countries should move towards the rate that equalises the prices of an identical basket of goods and services in each country. Our "basket" is a McDonald's Big Mac, which is produced in about 120 countries. The Big Mac PPP is the exchange rate that would mean hamburgers cost the same in America as abroad. Comparing actual exchange rates with PPPs indicates whether a currency is under- or overvalued.
满好玩的。比如说，中国的 Big Mac 价格是 ￥10.50，按照汇率 8.0135 换算成美元就是 $1.3103。但是在美国的 Big Mac 价格要 $3.10。
1.3103/3.10 - 1 = -0.577
也就是说人民币 Under valued 57.7%
不好意思，只在杭哥带动下去过垃圾食品店，所以不知道 Big Mac 究竟说的是不是巨无霸。