History of Lean Six Sigma

History of Lean Six Sigma

History of Lean Six Sigma

The use of statistics in manufacturing started in the 1920s at Bell Laboratories by Dr. Walter A. Shewhart, Dr. Harold Dodge, and Dr. Harry Romig. The military adopted the use of statistics in the 1940s during World War II. 

By the 1950s, Drs. Edwards Deming, Joseph M. Juran, and Armand V. Feigenbaun had made significant contributions to the quality engineering field by developing the Total Quality Management (TQM) system. Dr. Deming first taught quality control to the Japanese, and they were the first ones to embrace TQM. 

In the 1950s, Dr. Genechi Taguchi popularized the concept of “design of experiments” to improve product quality. The Japanese manufacturing industry made significant improvements in quality due to the wide use of statistical methods such as TQM. 

The Japanese were so successful in quality control that American customers preferred to buy products made in Japan rather than those made in the United States. As a result, Japanese manufacturers enjoyed large market shares in the United States, especially in the markets for automobiles and consumer electronics. 

To meet its customers’ needs, Toyota created the Toyota Production System (TPS) to deliver products of the right quality, in the right quantity, and at the right price.

This marked the beginning of Lean production. The key concept of Lean is to identify and eliminate the non–value-added steps in a process. These steps waste resources and add the chance of defects; eliminating them can accelerate the process and reduce the cost.

In 1980, NBC aired a documentary, If Japan Can...Why Can’t We?, which raised awareness of the quality issues among American industries. During the 1980s, U.S. corporations made tremendous strides to catch up with their Japanese counterparts. 

Six Sigma was developed partly due to this endeavor. In 1986, Six Sigma was first introduced by Motorola, where William Smith and Mikel Harry created the quality improvement process. 

In 1989, Motorola established the Six Sigma Research Institute, followed soon by AlliedSignal and General Electric (GE). Black & Decker, DuPont, Dow Chemical, Federal Express, Boeing, Johnson & Johnson, Ford Motor Company, General Motors, and many other companies initiated Six Sigma afterward. 

Most of the early proponents of Six Sigma were from the manufacturing and technology industries. As the methodology progressed, however, it spread to pharmaceuticals, financial institutes, toy makers, clothing retailers, the military, and many other sectors. By the late 1990s, about two-thirds of the Fortune 500 companies had embraced Six Sigma initiatives aimed at reducing cost and improving quality. 

Today, many companies require their employees to go through Six Sigma training. It is fair to say that Six Sigma has become an internationally accepted management system, a process im- improvement methodology, a technical problem-solving tool, and a global common language across different sectors.

In general, Six Sigma focuses on reducing the variation and defects in the performance of a product or process.


The performance of mass-produced products varies slightly from unit to unit; when this variation exceeds the tolerance, the product is a defect. 

Defects have to be tested, repaired, replaced, recycled, or trashed, adding waste and cost to the manufacturer. After the product is deployed in the field, a defect would cause customer dissatisfaction, repair charge, and potential loss of market share. To both the manufacturer and the consumer, consistent product performance adds value, which is why Six Sigma is so important. Six Sigma also allows more flexibility in choosing the nominal values for design parameters.

In the narrow statistical sense, a Six Sigma process produces 3.4 defective parts per million opportunities (DPMO). However, the objective of a Six Sigma project can also be a five sigma process, a three sigma process, or an eight sigma process, depending on the situation.

Many practitioners realized that Six Sigma alone might not be enough for some process improvement. Sometimes, we need to shift the mean in addition to reducing the variation. 

For example, for a process in manufacturing or service, it may be desirable to reduce the average and the variation of the cycle time. M. George was credited as the first person to propose the combination of Lean and Six Sigma in his book Lean Six Sigma: Combining Six Sigma Quality with Lean Production Speed. 

This new methodology, Lean Six Sigma, takes advantage of both: waste elimination and process acceleration in Lean, and variation reduction in Six Sigma. Lean Six Sigma is more effective than Lean or Six Sigma alone. As a result, it has become more and more popular as a tool for improving business and operational excellence over the last decade.

Even though statistics is a major part of the methodology, Lean Six Sigma is more than just a statistical tool for reducing product variation. It is also a process that can make a business more successful. Companies and organizations employ Lean Six Sigma to raise the quality of their products, eliminate waste in their processes, maintain the competitiveness of their products, and improve the financial bottom line. 

To survive in today’s global market, companies must continuously improve; no company is too big to fail!

This article is written by:

Dr. Lean Murali.

Lean Master Coach.

PS: The Article written above is from the learnings from various books on Lean & Six Sigma. Due credit to all the Lean & Six sigma thinkers who have shared their thoughts through their books/articles/case studies.

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