The Big Mac Index turns 40, and here's the beef: It's still relevant

An earlier version misspelled McDonald's - without the apostrophe. By Jules Rimmer

A simple product offers insight into the complicated world of currencies and their purchasing power

The ubiquitous Big Mac: cheapest in Jakarta, most expensive in Basel.

Happy Birthday to The Economist's Big Mac Index, which turns 40 this summer. In this era of deglobalization, trade imbalances and tariffs, forex manipulation and geopolitical realignment, an impartial analysis of a currency's real value is more important than ever.

In terms of U.S. economic policy, the centrality of the dollar's DXY value against other currencies has been emphasized by President Donald Trump: "If you look at China and Japan, I used to fight like hell with them, because they always wanted to devalue," he said.