Keystone · Public domain

Leontief built input-output analysis, a method for tracing how a change in one sector of an economy — say, steel output — ripples through every other sector that depends on it, and it became a standard tool for national economic planning worldwide. He won the Nobel Memorial Prize in Economic Sciences in 1973 for the work. Four of his doctoral students went on to win the same prize themselves: Paul Samuelson, Robert Solow, Vernon Smith, and Thomas Schelling.