In the late 1990s, Washington University professor Raphael Thomadsen visited McDonalds and Burger King locations in Silicon Valley. Thomadsen was interested in how these firms compete with each other. He collected information on the price of their signature sandwich, the Big Mac and the Whopper respectively, as well as other information about the store including whether it had a drive through or was located in a mall.
The map presents the locations of the various restaurants, where the size of the logo represents whether the price of the burger is in the top third, middle third or bottom third of prices in the area. The McDonald's Big Mac tends to be priced higher than Burger King's Whopper and prices tend to be higher in Mountain View and Palo Alto than further south in San Jose.
Does distance matter? Are prices lower when there are more outlets closer together?