I guess I would need to see the decision. I think a "Big Mac" is a fairly known thing. There even is a Big Mac inflation index, because of how uniform they are.
Edit: I guess it is a purchasing power parity index.
Here is a sort of interactive infograph version of the Big Mac index: https://www.economist.com/news/2019/01/10/the-big-mac-index
The data is on github: https://github.com/TheEconomist/big-mac-data