alt Hacker NewsCommodities. Raw materials with which all goods and services are made. Coffee, sugar, wheat, pound of beef, gasoline. Also products which are supposed to be identical like a Big Mac. Purchasing power is hard to measure but it’s a question studied deeply by economists.
Even the Big Mac index is flawed because it's not quite the same burger, since it's not made in the same regulatory environment, or by people compensated equally fairly.