The Pre-Six Sigma Eras: William Shewhart’s Statistical Control
The beginnings of the Six Sigma history brings us back to the roaring twenties, which was a time when the early developments in science and technology were still rough around the edges. It was during this era that an American statistician named William Shewhart showed how statistical methods could be used to instill quality control in industrial processes. In so doing, the technological invention could be expected to generate more reliable results.
William Shewhart manifested this while working as an engineer at Western Electric Company, where his work included providing technical advice to Bell Telephone Company. Shewhart was instrumental in helping the engineers reduce the frequency of failures and constant process adjustments.
It was at this point that this American statistician developed the framework for the “control chart”. The framework subsequently became a widely used tool to keep variations in manufacturing processes under statistical control. In using the said methodology, the trigger factors of the variations were distinguished either as an “assignable cause” or as a “chance cause”.
The control chart furnished the means for managing processes in ways that the results of the output could be predicted. The objective was to ensure quality turnout for every batch processed by using the available resources economically.
Those were the roots of the Six Sigma history.
Beginning 1925 through 1956, William Shewhart went into publishing a series of papers about the statistical control system he developed for Bell Telephone. In 1933, the American Society for Testing Materials (ASTM) came to adopt Shewhart’s control chart. During the World War II era, the American War Standards advocated Shewhart’s control chart as a means for improving production efficiency.
However, the turning point of the Six Sigma history came about in 1950 when another American statistician championed William Shewhart’s entire concept of statistical control. His name was W. Edwards Deming, to whom the system of rationalizing production-process improvement is attributed.
Deming’s analysis and rationalization concepts were based on William Shewhart’s statistical methods. They later came to be known in the manufacturing industry as Statistical Process Control (SPC) and Total Quality Management (TQM).
Quite interestingly, these concepts became great influences to Japan’s post-war industrial revival. Japan’s corporate managements widely received them as the keys to improving their manufacturing efficiency.
Pre-Six Sigma Era: W. Edwards Deming and the Japanese Connection
W. Edwards Deming and his philosophical views were highly revered by Japanese statisticians, so much so that he was conferred with the tribute of being the first Honorary Member of the Japanese Statistical Society. Around 1947, Japan’s manufacturing industries were suffering from a terrible reputation of producing poor quality items. Their goods were generally regarded as “junk”.
Japanese innovators, scientists and engineers were eager to learn Deming’s teachings about creating high quality product by controlling variations as a means for improving the Japanese manufacturers’ production processes. However, they found the publications of their Research Society of Commerce and Economics as highly technical and quite difficult to comprehend.
It was in the 1950s that the Union of Japanese Scientists and Engineers (JUSE) decided to invite W. Edwards Deming to teach them how to apply the statistical concepts for purposes of achieving quality in their manufacturing processes. This was in line with JUSE’s mission to help in rebuilding their country’s economy, as an aftermath of the World War II event.
Deming posed a challenge to the more-than-five-hundred attendees comprising government officials, professor and students: “The Japanese can do it within a span of five years if they closely adhere to my recommendations about process controls which involve consumer research and a redesigning of their products.” Thereafter, Deming was pleased to learn that the Japanese manufacturers were able to achieve their goals in four years’ time. Deming’s methodology became a part of Japan’s industrialization history.
This article’s retelling of the Six Sigma history continues on the next page, as the historical events lead to the American industries’ age of business process reengineering.
Pre-Six Sigma Eras: American Industries’ Age of Business Process Reengineering.
After spanning thirty years, the Japanese emerged as the top manufacturers of quality electronic goods by applying the statistical methods of controlling and measuring the variables in their processes. Based on W. Edwards Deming’s teachings, this was combined with responsible management for quality.
Ironically, however, the American manufacturing industry regressed during this period. The latter became more concerned with quantity over quality, and their products hardly reflected the principles of quality control.
By 1980, a complete role reversal had taken place. Western companies were turning to Japanese consultants like Masaaki Imai’s Kaizen, to learn about the Asian country’s method of applying Total Quality Management based on Deming’s teachings.
This was the era of business process reengineering (BPR)—wherein the Shewhart and Deming methodologies and principles were at the forefront of the movement. It was at Motorola that the beginnings of the Six Sigma history took place.
Signaling the Birth of Six Sigma at Motorola
Motorola’s quality engineers Bill Smith and Mikel Harry wrote and codified a report about their research on how the non-conformities affected the company’s performance.
Product defects that were not detected during quality control eventually surfaced during the product’s field life and at the hands of the consumer. Not only did this result in repairs of the finished products after the manufacturing processes but opportunity costs were being incurred as the defects tarnished and eroded the image of the manufacturer as well. Hence, substantial amounts of unnecessary costs were being incurred while the customers’ patronage was slowly being directed to other products that were proved more reliable and affordable.
This prompted the Motorola quality engineers to come up with the solution of instituting “logical filters” as a means to thresh out the non-conforming variables that occurred at different stages of production. By this, it meant deviations or non-conformities were detected and addressed at the earliest stages. Naturally, this could result in error-free output during the final stage.
As history has it, Motorola achieved resounding success by attaining $2.2 billion in cost savings in four years’ time. In 1988, Motorola became the first recipient of the Malcolm Baldrige National Quality Award, bestowed by the US government for its record-breaking improvement.
This signaled the birth of the Six Sigma discipline.
The Birth of Six Sigma and Its Teachings
Initially, the quality engineers developed their product and process-improvement programs and imparted their knowledge through the Motorola Institute.
In the year 1990, as Motorola’s resounding success reverberated throughout the American industries, other manufacturing giants like IBM, Texas Instruments and Kodak joined Motorola in establishing the Six Sigma Research Institute.
This is how Six Sigma Learning became an industry on its own as it went into the business of formally imparting the disciplines founded by Shewhart and Demings and developed as Six Sigma Methodology by the Motorola engineers led by Bill Smith .
In time, it became an important training process and was widely used as programs for product and process improvements. Its teachings involved the method of quantifying the problems found in the manufacturing processes into statistical and numerical forms. That way, engineers found it easier to formulate adjustments within a more accurate range of probabilities rather than rely on the traditional trial and error methods. The aim is to reduce the variations generated — down to a defect ratio of 3.4 parts per million.
Today, many companies include Six Sigma training and certifications as part of the hiring requirements for their key employees, regardless of industry trade or size. Critics call Six Sigma a fad and, at worst, a hoax. Perhaps by retelling the Six Sigma history down to its very roots, those who doubt the value of its teachings can be enlightened.
Reference Materials and Image Credit Section:
- New to Lean Six Sigma:iSixSigma https://www.isixsigma.com/index.php?option=com_content&view=article&id=201&Itemid=27