The Latte Index: Using the Impartial Bean to Value Currencies. The Latte Index is mostly for fun, but it’s also broadly in line with predictions made by the experts...
The “Latte Index”, developed by The Wall Street Journal, uses purchasing-power parity (PPP) – comparing the cost of the same good in different countries – to estimate which currencies are overvalued and undervalued.
In this case, the WSJ tracked down the price of a tall Starbucks latte in dozens of cities around the world. These prices are then converted to U.S. dollars and compared to the benchmark price, which is a tall Starbucks latte in New York City (US$3.45).
For example, the price of a latte in Toronto, Canada works out to US$2.94, which is about 14.8% under the benchmark NYC price. This suggests that relative to the USD, the Canadian dollar is undervalued.