Quality Pioneers – The Evolution of Six Sigma – Fourth in a Series

One of the first assignments in our Black Belt course deals with the origins of the continuous improvement approach that we know today as Six Sigma.  Many students are surprised to learn that the body of knowledge and the tools and techniques have been evolving for well over 100 years.

This article is the fourth and final in a series that will explore the contributions of and the strong personal relationships between a number of pioneers in the field of continuous quality improvement.  Listed in chronological order by the year of their birth, they are Vilfredo Pareto, Sir Ronald Fisher, Walter Shewhart, Dr. W. Edwards Deming, Dr. Joseph Juran, Dorian Shainin, Kaoru Ishikawa, Genichi Taguchi and Philip Crosby.

Genichi Taguchi (1924-2012) was a Japanese engineer and statistician who, beginning in 1950, developed a methodology for applying statistics to improve the quality of manufactured goods.  In 1950 Taguchi joined the Electrical Communications Laboratory (ECL) of the Nippon Telegraph and Telephone Corporation just as statistical quality control was beginning to become popular in Japan under the influence of Dr. Deming and JUSE.   ECL was engaged in a rivalry with Bell Labs to develop cross bar and telephone switching systems, and Taguchi spent his twelve years there in developing methods for enhancing quality and reliability. Even at this point, he was beginning to consult widely in Japanese industry, with Toyota being an early adopter of his ideas.  He left ECL in 1962 to teach and consult.

From 1954 to 1955 he was a visiting professor at Indian Statistical Institute, working with Sir Ronald R.A. Fisher and Walter Shewhart.  He served as the Executive Director of the American Supplier Institute beginning in 1982.

Taguchi made seminal and valuable methodological innovations in statistics and engineering, within the Shewhart-Deming tradition. His emphasis on loss to society; techniques for investigating variation in experiments and his overall strategy of system, parameter and tolerance design have been massively influential in improving manufactured quality worldwide.  Much of his work was carried out in isolation from the mainstream of Western statistics and, while this may have facilitated his creativity, much of the technical detail of Taguchi methods and its benefits to experimentation and research is only now being studied in the West.  He devised an equation to quantify the decline of a customer’s perceived value of a product as its quality declines.  This tells managers how much revenue they are losing because of variability in their production process. It is a powerful tool for projecting the benefits of a quality improvement program.  Taguchi was the first person to equate quality with cost – i.e. the cost of (poor) quality.

Phillip Crosby (1926-2001) started his career from the year 1952 as an inspector and progressed to department head at Martin-Marietta, Missile Building Company, Orlando Florida (USA) by 1959.   He became a corporate executive in ITT (International Telephone and Telegraph) in the year 1965, and worked there until 1979. In 1979 he started Philip Crosby Associates, an International Consulting firm for quality improvement.

Crosby popularized the idea of the Cost of Poor Quality that originated with Taguchi.  Crosby taught us to view the Next Operation as the Customer (NOAC).  He further created the mindset of Zero Defects (rather than “good enough” to meet a specification) as the objective for quality improvement.  He was quick to point out that zero defects is not something that originates with first-line workers.  To create a process that has zero defects, management must set the tone and atmosphere for employees to follow. If management does not create a system by which zero defects are clearly the objective, then employees are not to blame when things go astray and defects occur.  The benefit for companies of such a system is a dramatic decrease in wasted resources and in the time spent producing goods that consumer’s do not want.

In this series of four articles we discussed the work of quality pioneers Vilfredo Pareto, Sir Ronald Fisher, Walter Shewhart, Dr. W. Edwards Deming, Dr. Joseph Juran, Dorian Shainin, Kaoru Ishikawa, Genichi Taguchi and Philip Crosby.  They studied and built on the work of each other.

Pareto uncovered the relationships that Juran generalized into the Pareto principle.  Shewhart was a student of Fisher.  Deming was an intern under Shewhart, followed by a long collaboration between the two men.  Deming, Juran, and Ishikawa were all highly influential in Japan in the period following WWII, working within JUSE.  Ishikawa built upon Deming’s Plan-Do-Check-Act cycle.  Shainin developed his Red X concept based on the work of Pareto as well as his association with Juran.   Taguchi worked at Indian Statistical Institute with Sir Ronald Fisher and Walter Shewhart.  Crosby popularized the idea of the Cost of Poor Quality that originated with Taguchi.

And we all stand on their shoulders today as we learn, teach and apply the body of knowledge that we know as Six Sigma.

Your comments or questions about this article are welcome, as are suggestions for future articles.  Feel free to contact me by email at roger@keyperformance.com.

About the author:  Mr. Roger C. Ellis is an industrial engineer by training and profession.  He is a Six Sigma Master Black Belt with over 48 years of business experience in a wide range of fields.  Mr. Ellis develops and instructs Six Sigma professional certification courses for Key Performance LLC.   For a more detailed biography, please refer to www.keyperformance.com.