Lean Manufacturing and Six Sigma Definitions

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Lillian Gilbreth

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Lillian Evelyn Moller Gilbreth (May 24, 1878 – January 2, 1972) was an American psychologist, engineer, consultant, and educator. She earned a Ph.D. in applied psychology in 1915, which made her the first of the pioneers of industrial management to have a doctorate, and one of the first female engineers to earn a Ph.D. The topic of her dissertation was efficient teaching methods and titled Some Aspects of Eliminating Waste in Teaching.

Gilbreth and her husband, Frank Gilbreth, were efficiency experts who contributed to the study of industrial engineering, especially in the areas of time-and-motion studies and human factors. She is best known for combining psychology with the study of scientific management and engineering, specifically helping industrial engineers recognize the importance of the psychological dimensions of work. Additionally, the Gilbreths did research on fatigue study, the forerunner to ergonomics.

They developed a term called Therbligs (based on their name spelled backwards), which are 18 kinds of elemental motions that should be studied.

Due to discrimination within the engineering community, Gilbreth shifted her efforts toward research projects in the female-friendly arena of domestic management and home economics.

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.

In 1950, she was the first honorary member of the newly created Society of Women Engineers. In addition, Gilbreth was among the first to establish industrial engineering curricula in college and university engineering schools.



  • Society of Women Engineers
  • Amelia Earhart
  • Allan Mogensen
  • Jiro Kakuda





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