In 2014, the average gross annual salary for a full-time male worker in Switzerland was CHF 81,000, CHF 10,000 or 12.5% higher than that of an average woman. But what does this high level difference mean? Inspired by the Swedish statistician Hans Rosling, who passed away recently, I decided to dig deeper to see what was behind this top line pay difference.

The Economist invented the Big Mac index in 1986 as a tongue-in-cheek guide to currency valuations. Because the well-known burger is the same throughout much of the world, the magazine thought it could be used as a measure of how over or undervalued a currency was. An overpriced burger suggests an overvalued currency and a cheap one an undervalued currency.