The Hedgehog Model for Decision Making
I'm a huge fan of any models that find applicability beyond their intended domains and there are few quite as versatile and useful as The Hedgehog Model.
In his seminal book "Good to Great", Jim Collins examines 1,435 businesses over a period of 40 years in order to answer the question "what separates the good companies from those which make the leap and become great companies?" Over the course of his analysis, he uncovers a variety of factors that drive this distinction but one of the most fundamental concepts he explains is "the Hedgehog".
This idea is based on a fragment attributed to the ancient Greek poet Archilochus which says "a fox knows many things, but a hedgehog one important thing." Both these animals have survived successfully by deploying greatly different strategies. The fox is clever -- she knows a great many things and tends to rely on her intelligence to hunt and survive. The hedgehog is a far simpler creature -- when she is threatened, the hedgehog simply curls up into a ball and points her spines outwards.