This illustration accompanied an article by Tim Harford for his column The undercover economist, originally published in the FT, and published again in G magazine with my illustration for the past 10 years or so.
Forty years ago a German economist, Reinhard Selten, published a working paper with the title “The chain store paradox”. It was simple and profound and showed a discomfiting disconnect between the fashionable mathematical tools known as “game theory” and the recommendations of common sense.
This is the set-up. Imagine a chain store with 20 branches, one in each of 20 small towns. Lacking any competition, these branches charge high prices and are lucrative. In each town, an entrepreneur is considering opening a rival shop. These 20 local entrepreneurs will, one by one, decide whether to compete against the chain store or to sink their capital into something else.
Read it all here.