Lean Manufacturing and Six Sigma Definitions

Glossary terms, history, people and definitions about Lean and Six Sigma

Frank Gilbreth

Frank Bunker Gilbreth (July 7, 1868 – June 14, 1924) was an American engineer, consultant, inventor, and author known as an early advocate of scientific management.

Frank Gilbreth and his wife, Lillian Gilbreth, were efficiency experts who contributed to the study of industrial engineering, especially in the areas of time-and-motion studies and human factors.

He discovered his interest in efficiency when we started out as a construction worker, looking for ways to make bricklaying faster and easier. He next worked as a general contractor constructing buildings. He was the first to propose the idea of a “caddy” to hand surgical instruments to a surgeon. He also devised the standard techniques used by armies around the world to teach recruits how to rapidly disassemble and reassemble their weapons.

Later, he started to collaborate with Lillian and they studied manufacturing and clerical employees in all sorts of industries to find ways to increase output. They later founded a management consulting firm, Gilbreth, Inc.

The Gilbreths did research on fatigue study, the forerunner to ergonomics, and they developed a term called Therbligs (based on their name spelled backwards), which are 18 kinds of elemental motions that should be studied.

He is credited with introducing the flow process chart to members of The American Society of Mechanical Engineers (ASME) in 1921 in a presentation titled “Process Charts—First Steps in Finding the One Best Way.” It was later integrated into the industrial engineering curricula along with other approaches and techniques.

Cheaper by the Dozen (1948) and Belles on Their Toes (1950), written by two of their children (Ernestine and Frank Jr.), tell the story of their family life and describe how time-and-motion studies were applied to the organization and daily activities of their large family. Both books were later made into feature films.



  • Lillian Gilbreth
  • Allan Mogensen
  • Institute of Industrial and Systems Engineers (IISE)
  • American Society of Manufacturing Engineers (ASME)





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