Why Six Sigma is not TQM

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Copyright © 2001
by Thomas Pyzdek, all rights reserved

My colleagues often tell me that there is no real difference between Six Sigma and TQM. “Show me where Six Sigma involves anything new.” Six Sigma employs some of the same tried-and-true tools and techniques of TQM. Both Six Sigma and TQM emphasize the importance of top-down support and leadership. Both approaches make it clear that continuous improvement of quality is critical to long-term business success. The PDSA cycle used in TQM is not fundamentally different than the Six Sigma DMAIC cycle.

But there are differences. Critical differences. And these differences explain why the popularity of TQM has waned, while Six Sigma’s popularity continues to grow.

The difference, in a word, is management. TQM provided only very broad guidelines for management to follow. Guidelines so abstract and general that only the most gifted leaders were able to knit together a successful deployment strategy for TQM. Business magazines and newspapers reported widespread failure of TQM efforts. True, solid research showed that organizations which succeeded in successfully implementing TQM reaped substantial rewards. But the low probability of success deterred many organizations from trying TQM. Instead, many organizations opted for ISO 9000. ISO 9000 promises not world-class performance levels, but “standard” performance. But it provides clear criteria and a guarantee that meeting these criteria will result in recognition. In contrast, TQM offered a mushy set of philosophical guidelines and no way to prove that one had accomplished their quality goals.

Unlike TQM, Six Sigma was not developed by techies who only dabbled in management. Six Sigma was created by some of America’s most gifted CEOs. People like Motorola’s Bob Galvin, AlliedSignal’s Larry Bossidy, and GE’s Jack Welch. These people had a single goal in mind: to make their businesses as successful as possible. Once they were convinced that the tools and techniques of the quality profession could help them do this, they developed a framework to make it happen. Six Sigma.

Speaking as a member of the quality profession, we knew that we had a winning set of tools that could solve quality problems in manufacturing. Total quality control, invented in 1950, showed that product quality could be improved by expanding quality efforts into upstream areas such as engineering and purchasing. We even had limited success in using our tools to improve quality in administrative areas by reducing errors in service transactions. But despite these successes we suffered from a number of shortcomings. For example:

  • We focused on quality and ignored other critical business issues. Quality trumped everything else. Of course, this made no business sense and often lead to organizations that failed despite improved quality.
  • We created a quality specialty that suffered from all of the same suboptimization problems as other functions within the organization. Despite all of our talk about a systems perspective, when push came to shove we fought for our point of view (and our budget) just like everyone else. In the typical organization this resulted in other departments considering “quality” to be the turf of the quality department. Thus, they backed off of-or never started-efforts of their own.
  • We emphasized minimum acceptance requirements and standards, rather than striving for ever increasing levels of performance.
  • We never developed an infrastructure for freeing up resources to improve business processes.
  • We developed a career path in quality. Quality professionals tended to lack subject matter expertise in other areas of the company. This division of labor, combined with functionally specialized organization, made it difficult to improve quality beyond a certain level. (I estimate that this type of organization tops out at about 3.5 sigma.)

The CEOs were able to see what the problems were, and to create an approach that fixed them. Six Sigma addresses all of these issues:

  • Six Sigma extends the use of the improvement tools to cost, cycle time, and other business issues.
  • Six Sigma discards the majority of the quality toolkit. It keeps a subset of tools that range from the basic to the advanced. Six Sigma discards esoteric statistical tools and completely ignores such staples of the quality professional as ISO 9000 and the Malcolm Baldrige criteria. Training focuses on using the tools to achieve tangible business results, not on theory.
  • Six Sigma integrates the goals of the organization as a whole into the improvement effort. Sure, quality is good. But not independent of other business goals. Six Sigma creates top-level oversight to assure that the interests of the entire organization are considered.
  • Six Sigma strives for world-class performance. The Six Sigma standard is 3.4 PPM failures per million opportunities. It goes beyond looking at errors. The best of the Six Sigma firms try to meet or exceed their customer’s expectations 999,996.6 times out of every million encounters.
  • Six Sigma creates an infrastructure of change agents who are not employed in the quality department. These people work full and part-time on projects in their areas or in other areas. Six Sigma Black Belts do not make careers in Six Sigma. Instead, they focus on Six Sigma for two years and then continue their careers elsewhere. Green Belts work on Six Sigma projects while holding down other jobs. These subject matter experts are provided with training to give the skills they need to improve processes. Six Sigma “belts” are not certified unless they can demonstrate that they have effectively used the approach to benefit customers, shareholders, and employees.

There are many other differences as well. Having worked with organizations that have done TQM well and Six Sigma well, I can tell you that successful programs of both types look very much alike. But Six Sigma, by clearly defining this “look,” makes it easier for organizations to succeed by providing a clear roadmap to success. Don’t get me wrong; I’m not saying that succeeding at Six Sigma is easy! But organizations are more willing to invest the effort if they know that a pot of gold awaits them at the end.

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