The Big Mac Index uses Purchasing Power Parity (PPP) in comparing the price of the ubiquitous Big Mac across countries relative to its price in the USA. PPP refers to the idea that exchange rates across two countries should be equal to the relative price of a basket of goods and services in both countries.

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For those that don't know, PPP is a way of measuring the relative value of currencies, accounting for things like cost of living.

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