The Economist’s Big Mac index, a PPP analysis hitting its 40th year of kicking ass, demonstrates just how difficult i...

The Economist’s Big Mac index, a PPP analysis hitting its 40th year of kicking ass, demonstrates just how difficult it is to track the timely parity of global currencies. …for as long as currencies remain unmoored, and the Big Mac remains consistent, our index will serve a useful purpose—however distasteful its critics may find it.