Lillian Gilbreth – How She Contributed to the Development of Modern Lean Six Sigma

It is no stretch of the imagination to see that Lean and Six Sigma are male-dominated fields. Indeed, it is men who are most talked about when it comes to the development and popularization of Lean Six Sigma. Many people don’t know that women have played an important role in moving these two methodologies forward.

In Six Sigma, for example, you have Mikel Harry and Bill Smith, who both worked for Motorola in the 1980s and developed the methodology to improve manufacturing operations. For Lean, you have Frederick Winslow Taylor (1856-1915), whose work is considered to have set the stage for the development of Lean Six Sigma. 

Beyond that, you have Walter Shewhart, the inventor of Statistical Process Control. You also have Bob Galvin, who, as the CEO of General Electric in 1987, launched “The Six Sigma Quality Program”. This initiative made it everyone’s responsibility to help the company achieve Six Sigma, as well as tied Six Sigma to their performance measures and KPIs.

But what about women? Here, you have another big contribution coming from Lillian Gilbreth. Together with her husband, Frank Gilbreth, their time-motion study made many regard them as efficiency experts who took scientific management to the next level. And it also showed that Lillian was among the people who understood the principles of Lean and Six Sigma decades before they were officially developed.

Lillian, who is among the first women to ever hold a PhD, had a fascination with efficiency. She and Frank had 12 children, which is a very large family, and they managed to raise their family according to the principles and theories of their time-motion studies. This is described in the semi-autobiographical book called “Cheaper by the Dozen”. The book was written by Frank Bunker Gilbreth Jr. and Ernestine Gilbreth Carey, who were their children.

Based on these studies the Gilbreth’s came up with three points that can increase the efficiency of workers, as well as their welfare, in an organization. These are:

1. Minimize motion when performing a particular task
2. Motion and time should be studied incrementally
3. Increasing efficiency increases the bottom line and job satisfaction

In regards to the first point, Lillian and her husband came up with the term “therbligs”, which is their last name spelt backward. This term refers to the 18 elemental motions that are performed during a task. They studied these motions and determined which ones were necessary and which ones weren’t. And to increase efficiency, they eliminated the unnecessary ones. This is starting to sound like Six Sigma, which aims to improve the performance of processes through the reduction or elimination of waste (anything that doesn’t add value).

The 18 therbligs are:

1. Search
2. Find
3. Select
4. Grasp
5. Hold
6. Transport Loaded
7. Transport Empty
8. Position
9. Assemble
10. Use
11. Disassemble
12. Inspect
13. Preposition
14. Release Load
15. Unavoidable Delay
16. Avoidable Delay
17. Plan
18. Rest

One thing to understand is Lilian’s work was being conducted in the early 1900s. Her work, especially in the field of engineering, faced a great deal of discrimination. This prompted her to channel her research towards home economics and domestic management to escape the discrimination since these were more female-focused areas. But thanks to the work she did on the time-motion study, Lean Six Sigma became one step closer to reality.

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