History of Six Sigma: Exploring the Roots

Six Sigma History

In the field of quality management, the Six Sigma methodology stands out due to its profound impact on process improvement across industries. With its origins in statistical analysis and data-driven decision-making, Six Sigma is the premier methodology for organizations that seek sustainable processes that realize business efficiencies and provide high customer satisfaction.

This article highlights Six Sigma’s early beginnings and those credited for its creation, evolution, integration with lean principles, and examples of its use in various industries.

What is the History of Six Sigma

Six Sigma is a methodology that aims to improve processes by reducing defects and variability. It’s based on the idea that a process should produce no more than 3.4 defects per million opportunities, which equates to six standard deviations (sigma) between the process mean and the nearest specification limit. This high standard ensures processes are as close to defect-free as possible. Six Sigma uses statistical tools and a structured certification system, with belts ranging from White (basic understanding) to Master Black Belt (highest expertise).

Six Sigma was introduced by Bill Smith at Motorola in 1986 to improve manufacturing quality. Motorola registered it as a trademark in the early 1990s. Companies like Honeywell and GE adopted it, with GE’s CEO Jack Welch making it central to his strategy in 1995. By the late 1990s, about two-thirds of Fortune 500 companies had started Six Sigma initiatives. It’s often integrated with lean manufacturing principles to reduce both waste and defects.

Six Sigma Belt Levels

Six Sigma Belts

Six Sigma’s belt system, inspired by martial arts, was first formalized in a 1988 contract between Unisys and Mikel Harry. It denotes certified levels of expertise and training in process improvement. The system starts with the White Belt, signifying foundational understanding. Next is the Yellow Belt, indicating deeper knowledge and ability to participate in project teams.

Green Belts can work independently and lead projects or assist Black Belts. Black Belts have advanced understanding, can lead multiple projects, and solve challenging problems. At the top is the Master Black Belt, the highest level of expertise. They’re responsible for strategic implementation and mentoring within Six Sigma.

Six Sigma Methodology Founders

Six Sigma’s history starts with the need to improve manufacturing processes systematically. From statistical experts to visionary leaders, these individuals played pivotal roles in molding and popularizing Six Sigma. 

Timeline of Six Sigma History

Six Sigma History: Walter Shewhart 1920s

With his combination of statistics, engineering, and economics into sustainable processes, Walter A. Shewhart is called the “father of statistical quality control.” The American Society for Quality (ASQ) gave their first Honorary membership to Shewhart in part due to his invention of the control chart, “…a simple but highly effective tool that represented an initial step toward what Shewhart called “the formulation of a scientific basis for securing economic control.”‘

Six Sigma History: Bill Smith at Motorola 1980s – 1990s

As an engineer at Motorola in the 1980s, Bill Smith began applying statistical analysis to achieve process improvement. Smith started to identify and remove the causes of defects through statistical analysis, thus minimizing variability in the associated processes. In 1985, he approached Motorola’s CEO, Bob Galvin, with a proposal to reduce defects by reducing process variations. Through his work, Smith realized that this statistical process improvement method could consistently enhance product quality. Smith is the principal founder of what became the Six Sigma methodology.

Six Sigma History: Mikel Harry at Motorola 1980s -1990s

Mikel Harry worked with Bill Smith to create a four-stage problem-solving approach:

measure, analyze, improve, and control (MAIC). [Later iterations included a fifth stage of “D” to create the Define, Measure, Analyze, Improve, and Control.) The Six Sigma quality management methodology incorporated Smith and Harry’s approach. Harry’s book, Six Sigma: The Breakthrough Management Strategy Revolutionizing the World’s Top Corporations (Crown Business, 2000), has been a bestseller in The Wall Street Journal, Bloomberg Businessweek, and Amazon.com.

Six Sigma helped Motorola realize significant financial savings in their organization; at one point, they documented more than $16 billion in savings due to Six Sigma efforts.

Six Sigma History: Jack Welch at GE 1990 – 2000s

Smith and Harry’s quality management approach took off when Jack Welch, CEO of General Electric (1981 – 2001), embraced Six Sigma and made it a cornerstone of the corporate culture of this global multi-conglomerate. Under Welch’s leadership, GE integrated Six Sigma into its organizational business culture to realize significant financial savings and inspire other companies to use the quality management approach.

Six Sigma’s Evolution Through Adaptability 

Since its inception, Six Sigma has changed, evolving from a manufacturing quality control method to a universal tool for process improvement across industries such as finance, healthcare, and IT. The evolution of Six Sigma is why it is so long-lasting; Six Sigma applies to various products, industries, and processes. Through carefully monitored process improvements, quality is achievable in almost any setting.

  • early 20th century | Frederick W. Taylor and Walter A. Shewhart laid the foundation for scientific management and statistical control of processes
  • post-World War II era | Joseph M. Juran emphasized statistical techniques and the importance of management commitment; W. Edwards Deming introduces Total Quality Management (TQM) as a holistic approach that integrates quality into every aspect of an organization.
  • 1990s: Bill Smith and Mikel Harry found what they coined “Six Sigma” while at Motorola, and later, Jack Welsh promoted it across General Electric.

Over time, the Six Sigma methodology has adapted to meet the needs of multiple organizational processes and problems. Today, concepts like Lean and Agile methodologies complement traditional quality management practices to help companies achieve continuous improvement.

Lean Six Sigma

Lean, a methodology focused on waste reduction, and Six Sigma, which concentrates on reducing defects, naturally complement each other. The combination, known as Lean Six Sigma, offers a comprehensive approach to process improvement. Six Sigma founding contributor Harry told Quality Digest in a 2006 interview

[“People forget that Six Sigma is not an absolute; it’s a vision,” he said. It’s a vision at the business, operations, and process levels. Six Sigma relies on tools. Lean Sigma, ISO Sigma, and other little “X” Sigmas are exploratory tributaries.]

Organizations that successfully implement Lean Six Sigma enjoy cost reduction, improved customer satisfaction, and streamlined processes.

Six Sigma’s Benefits

Six Sigma remains relevant in the current business landscape because it adapts to technological advancements and global challenges. Businesses that embrace Six Sigma and commit to fully incorporating it across the organization may realize benefits, including reducing errors and waste, maximizing resources, and higher customer quality scores.


Six Sigma’s future is bright as organizations seek innovative ways to enhance efficiency and quality. While the methodology has evolved to include specific types like Lean Six Sigma, Six Sigma must integrate advanced technologies such as artificial intelligence, machine learning, and data analytics to remain relevant. By leveraging these technological tools, Six Sigma can continue to evolve with the inclusion of predictive and proactive insights. A company that can address potential processes or customer issues before they escalate has a distinct market advantage.

The use of Six Sigma methodologies will continue to grow in more non-manufacturing industries, such as healthcare and service, by organizations seeking a proven systematic approach to quality management. Six Sigma’s future depends on its ability to evolve, integrate new technologies, and adapt to the changing dynamics of the business environment while maintaining its core principles of quality and efficiency. Continuous improvement, realized through the Six Sigma methodology, is critical to any organization seeking to remain competitive and bring customers the best products and services. 

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