Concrete language helps people, especially novices, understand new concepts. Abstraction is the luxury of the expert. If you've got to teach an idea to a room full of people, and you aren't certain what they know, concreteness is the only safe language. (…) When Boeing prepared to hunch the design of the 727 passenger plane in the 1960s, its managers set a goal that was deliberately concrete: The 727 must seat 131 passengers,1 fly nonstop from Miami to New York City, and land on Runway 4-22 at La Guardia. (The 4-22 runway was chosen for its length—less than a mile, which was much too short for any of the existing passenger jets.) With a goal this concrete, Boeing effectively coordinated the actions of thousands of experts in various aspects of engineering or manufacturing. Imagine how much harder it would have been to build a 727 whose goal was to be "the best passenger plane in the world".