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Six Sigma™ and Kaizen Compared: Part 1 (Revised) - Raphael L. Vitalo, Ph.D. Introduction
A comparison of Six Sigma™ and Kaizen is a complicated task for several reasons. First, each term has more than one meaning. Second, there are two different levels at which to compare Six Sigma™ and Kaizen. You can compare them at the level of making an improvement to a business process (the event or project level) or at the level of a total approach to improving the success of a business. Third, there are many dimensions on which you can compare these approaches—e.g., their respective origins and the various meanings each term has, their scopes of application, the purposes each approach accomplishes, the benefits each produces, etc. Fourth, there is a difference between what people who promote these approaches say and what actually happens in practice. Which do you use to make your comparison? Given these complexities, this is my plan for comparing each approach. I will contrast them in relation to the following nine topics:
My main focus will be on the business process improvement level. I will accomplish this comparison over a series of articles tackling one or more of the topics listed above. I hope that you will investigate each of these separate issues on your own, and share back what you find. In this article, I will share what my research has uncovered about the origins of Six Sigma™ and Kaizen, the various meanings of each term, and the scope each approach claims. I will begin, however, with a review of the Quality Model, since both these methods emerged as implementations of the Quality Model or as instruments for accomplishing one or more of its goals. As to the issue of what proponents say versus what happens in fact, I will try to share that within each section of the comparison, as best I can.
The Quality Model The Quality Model is a strategy for commercial success that rests on the idea that businesses succeed to the degree that they satisfy their customers’ real requirements and continuously improve in achieving this result. Methods and approaches such as Statistical Process Control [SPC] and Statistical Quality Control [SQC]; Quality Planning, Implementation, and Improvement (Juran Trilogy); Total Quality Management [TQM], Lean, and Six Sigma™ are rooted in the Quality Model. All such approaches1 share a core set of principles that, when applied, achieve Quality’s goal and lead a company to high performance. These principles are the foundations of the Quality Model. The principles are:
As these principles indicate, success is rooted in understanding ones customers real requirements, involving everyone in owning and acting to satisfy those requirements, and continuously improving in accomplishing that result (Exhibit 1).
Various quality-model thinkers have added content to the model they feel should be part of its core principles—e.g., that quality must be managed and cannot be allowed to happen on its own. We do not include these as basic principles of the quality business model because they are part of every Western model for success. To say that quality must be managed and cannot be allowed to happen on its own is simply to say that you must focus on your goals and work systematically to achieve them. This may be a more Western than Eastern concept, but, at least within a Western cultural view, it applies to all endeavors in life. On the other hand, to assert that your driving purpose as a business must be “satisfying the customers’ real requirements” says something that is not commonly held. There are many business models for success and much practice that says businesses succeed on the basis of making profits. “Making profits” and “satisfying customers” are not equivalent. If I drive toward one, I may or may not drive toward the other or realize it to the same degree. For example, one way companies have succeeded in making huge profits and becoming giants in their industry is by restricting the customers’ access to alternative products or services (e.g., IBM in the 1960s and 1970s and Microsoft since its inception). IBM built in proprietary components to its “big iron” computers that forced customers to return to it for hardware upgrades and software. Microsoft required computer vendors to pay it for every machine they built, whether or not they loaded it with Microsoft’s operating system. If they did not, they could not load MS DOS on any of their machines. Consequently, manufactures only loaded MS DOS since adding any other operating system would increase their costs. These market controlling methods are antithetical to quality; nonetheless, many companies seek to use them and many more wish they could.
The Origins of the Quality Model Many people contributed to the development of the Quality Model. One of its earliest contributors was Walter Shewhart who developed the method of process charting while working at Bell Laboratories in the late 1920’s. He reported his work and methods in his book, “Economic Control of Quality of Manufactured Product” in the 1930’s. W. Edwards Deming became involved with Shewhart and they ran courses over several years on measuring and controlling variation in work processes in the United States. In 1940, Deming took a position at the U.S. Census Bureau, just at the time that the Bureau shifted its procedure from a complete count to a sampling method. Upon completion of the 1940 census, Deming began to introduce Statistical Quality Control (SQC) into industrial operations. In 1941, he and two other experts began teaching SQC to inspectors and engineers. The Quality movement transferred to Japan in "1946 with the U.S. Occupation Force's mission to revive and restructure Japan's communications equipment industry. General Douglas Mac Arthur was committed to public education through radio. Homer Sarasohn was recruited to spearhead the effort by repairing and installing equipment, making materials and parts available, restarting factories, establishing the equipment test laboratory (ETL), and setting rigid quality standards for products. Sarasohn recommended individuals for company presidencies, like Koji Kobayashi of NEC, and he established education for Japan's top executives in the management of quality. Furthermore, upon Sarasohn's return to the United States, he recommended W. Edwards Deming to provide a seminar in Japan on statistical quality control (SQC)" (Pecht and Boulton, 1995). In the 1950’s Deming initiated wide scale statistical training in Japan. His approach emphasized statistical methods that monitored variation on work processes and used systematic investigation and analysis (e.g., process charting, Pareto charts, histograms, cause-effects diagrams) to detect the sources for variation. He identified four types of variability: common, special or assignable cause; tampering; and structural (Joiner and Gaudard, 1990). A manager’s first responsibility is to understand variability and drive it out of all processes. Common variability was random and inherent in the processes as designed and more difficult to eliminate. Special cause variation was assignable to causes through investigation. When identified, it could be eliminated. Both SPC and Statistical Quality Control (SQC) embody this emphasis, but all Quality approaches incorporate attention to failures in satisfying customer requirements and use the same problem solving tools to eliminate them. To my knowledge, all the “event-level” tools used in what is now termed “Six Sigma™” were taken from SPC and SQC. Deming did much more than focus on variation and tools for eliminating it. He developed a broad perspective that encompassed a view of the worker, how management should involve workers in the business, the role of management including its responsibilities and accountabilities, and the mind set that is required for the Quality Model to succeed (Deming, 1982, 1988). Deming's evolution of thinking and the contributions of other Quality Model practitioners raised the level of quality management from the factory floor to the total organization. In 1954, Dr. Joseph M. Juran of the United States introduced formalized quality planning methods that addressed a systematic, business-level2 approach to implementing the Quality Model. His methodologies for quality planning, implementation, and improvement are known as the Juran Trilogy (Juran 1982, 1988). Juran "...stressed the importance of systems thinking that begins with product designs, prototype testing, proper equipment operations, and accurate process feedback. His business-level approaches use a form of Quality Function Deployment (QFD) to systematically assess all products and processes against customer requirements. This assessment uncovers waste and identifies opportunities for improving quality. They also incorporate the use of worker teams to uncover problems in the work place and solve them. Quality Circles is an early example of day-to-day, at-the-work-site improvements made by the team who implemented the work process. Juran's seminar became a part of JUSE's [Union of Japanese Scientists and Engineers] educational programs. His work spurred the move from SQC to TQC (total quality control) in Japan. TQC included company-wide activities and education in quality control (QC), QC circles and audits, and promotion of quality management principles" (Pecht and Boulton, 1995). Philip M. Crosby is credited with further expanding methods for involving people3 and leveraging more of the day-to-day knowledge workers developed through their everyday activities. These expanding methods also used special teamed problem solving sessions where workers were brought together to address larger problems that frequently went beyond their local work process. The “Work Out” method that General Electric Corp. introduced in the 1980’s was essentially a re-labeling of the teamed problem-solving approach.
Summary Thus far, we can make these points.
Quality's Progeny: Lean and Six Sigma™ Kaizen itself is not a comprehensive approach to implementing the Quality Model. The Lean Enterprise4 model, with which Kaizen is associated, addresses that level of action. In contrast, the term Six Sigma™ is applied both to a comprehensive business-wide approach to implementing the Quality Model and to the limited activity of improving a business process.
Lean's Emergence and Extension of the Quality Model James Womack and his colleagues formalized the lean manufacturing model by studying the Toyota Production System (TPS) and other Japanese companies' approaches to commerce and comparing them with those employed by a large array of automotive companies around the world. The study was implemented in 1985 by the International Motor Vehicle Program located in the Center for Technology, Policy, and Industrial Development at the Massachusetts Institute of Technology. Its goal was to enable automobile manufacturers worldwide to advance the prosperity of their host countries and improve the work life of industry employees by transferring knowledge of the more competitive approaches implemented by Japanese companies like Toyota. These companies all employed the Quality Model as developed by Deming, Juran, and others. The study lasted five years, had 36 sponsoring governmental and industry organizations, produced 116 scholarly publications, and culminated in the publication of The Machine That Changed the World (Womack, James P.; Jones, Daniel T.; and Roos, Daniel, 1991). It identified the Toyota Motor Company's TPS approach as the best representation of the competitively superior approaches employed by Japanese firms. It introduced the term "lean production" to characterize TPS' manufacturing strategy and contrasted it with "mass production," which was the norm. Over the next decade and half, the "lean production" model was refined and elaborated into "lean thinking." Toyota's strategic perspective and operating methods became expressed in its depiction of the "lean enterprise." Lean adds several elements to the basic tenets of the quality model (Vitalo et al, 2007). Lean operationalizes the customer's experience of "satisfaction" as value received. It defines value as any feature for which a well-informed and reasonable customer is willing to pay. Lean clarifies the ways a business "adds value" to its offering. It includes the quality model's basic approach—namely, understand in ever- richer detail the customer's real requirements and satisfy them. It develops in richer detail, however, a second way—eliminate any activity from your business that does not produce value. Lean also broadens the scope of action a business must undertake to succeed. It must improve its own operations and those of its suppliers and customers (extended value stream) in order to fully root out waste and maximize value for its customers. Lean's perspective of business stakeholders expands communally Quality's thinking. Again, following the Toyota perspective, lean widens the recognition of stakeholders beyond customers and suppliers to include employees, owners, governments, and the communities within which the business operates.5 Kaizen as a process improvement methodology is one tool within the Lean tool kit.
Six Sigma™ Origins Six Sigma™, as a business-level strategy, is a “re-labeling” of the approach used by Motorola, Inc. to implement the Quality Model during the 1980’s. As Ramias reports with regard to Six Sigma's origins, "Truth is, the efforts to improve quality through use of statistics went back to the early 1980s, and the creation of Six Sigma as a program was essentially a repackaging of tools and methods going all the way back to Deming." (Ramias, 2005, page 2). More precisely, Motorola's approach was most associated with Joseph M. Juran, a Quality pioneer and contemporary of Deming. His approach to achieving competitive success integrated both the measurement-oriented Quality methods like SPC and SQC with team-oriented improvement efforts like Quality Circles, team problem solving, and other involving methods. It has a business-level planning component as well as event-level improvement methods. At the event-level, it emphasized the measurement-oriented and quantitative analysis elements that were pioneered and developed in SPC and SQC. Yet, in practice, it included problem solving activities that relied on the knowledge that workers developed through their experience of doing the work and their observations of how current methods succeeded and failed (Pande, Newman, and Cavanagh, 2002). Motorola's initial focus was on product quality and the elimination of defects. Beginning in 1986, it began to focus on process capability largely due to the writing and influence of Bill Smith, a Motorola reliability engineer. When Bill Smith gave birth to the term six sigma, the term was a target for performance and not Motorola’s approach to reaching that performance. Smith was attempting to focus attention on creating processes that consistently produced outputs to specification. A six sigma6 process was one that produced less than 3.4 defects per million opportunities (Pande, et al., 2002; page 179). In 1987, Motorola's total approach to quality became rebadged as Six Sigma. In 1991, the term was trademarked. Its commercialization has been credited to Mikel Harry who was initially a consultant with Motorola, then an engineer at Motorola, and finally the head of its Six Sigma Academy. While it is popular to credit Six Sigma with billions of dollars in savings and Motorola's winning of the Malcolm Baldrige National Quality Award in 1988, in fact, it appears to have had little contribution to these achievements. According to Ramias (2005), "Motorola won the Baldrige Award not because of its formal Six Sigma program that kicked off in 1987 but because it had made truly awesome improvements in both quality and cycle time over the preceding 8 years. Those achievements were a result of all the TQM and BPI [the business process improvement method developed by Rummler] efforts going on, and they weren’t viewed as a single comprehensive program called 'Six Sigma' or anything else…except in hindsight" (2005, page 2). In fact, "As a formal program, Six Sigma was barely in place when the Baldrige Award was obtained" (2005, page 2). For further clarification of Six Sigma's origins and contributions, see The Mists of Six Sigma™ (Ramias, 2005). Six Sigma™, as a business process improvement method, is simply a problem solving strategy theoretically rooted in the measurement of process variability and guided by customer requirements. In fact all quality improvement methods—including Kaizen—are problem solving methods. They all use the same process: 1. Describe the problem, 2. Analyze it root causes, 3. Develop ways to eliminate causes, 4. Implement solutions, and 5. Measure success. In support of Six Sigma™'s commercialization, a new set of terms were developed to express this process—Define, Measure, Analyze, Improve, and Control (DMAIC). In fact, DMAIC is a rather nifty way to capture the basic problem solving process—but, it adds nothing except "niftiness" to solving problems. In the next article, we will probe in more detail how the process works in theory and fact and compare it with Kaizen.
Summary Thus far, we can make these points.
Kaizen’s Origins and Scope Kaizen (pronounced ki-zen) is a Japanese word constructed from two ideographs, the first of which represents change and the second goodness or virtue. Kaizen is commonly used to indicate the long-term betterment of something or someone (continuous improvement) as in the phrase Seikatsu o kaizen suru which means to “better one’s life.” The term Kaizen is used in two ways. The first use is consistent with the phrase continuous improvement. The second use is as the label for a group of methods that improve work processes. Kaizen as Continuous Improvement In its first use, Kaizen means the pursuit of perfection in all one does. In this sense, Kaizen represents the element of continuous improvement that is a fundamental part of the Quality Model. In a business context, it includes all activities, personal and teamed, that leverage learning to make processes better at satisfying customer requirements. As the principle of continuous improvement, Kaizen has its origins in W. Edwards Deming’s 14 points. Point 5 states, “Improve constantly and forever" the system of production and service (Deming, 1982). Kaizen as Methods for Work Process Improvement In its second use, Kaizen identifies a group of methods for making work process improvements. The methods that have been placed under the label Kaizen are varied and range from suggestion systems (Teian Kaizen) to planned events conducted in the workplace that systematically uncover waste in a work process and eliminate it (Gemba Kaizen). In this latter use, Kaizen's origins are in World War II (Huntzinger, 2002; Kato, 2006). Kaizen, then known as Job Methods training, was a simple and effective process that enabled workers—initially supervisors—to devise ways to greatly improve the yield from work processes. Its development was spurred by the World War II necessity to produce very much more of everything that was needed for the war effort, faster than anyone ever had done in the past. Before going further into Kaizen's origins as a method for making improvements, let's clarify the varieties of methods that now fall under the label Kaizen.
Varieties of Kaizen Methods The collection of Kaizen methods can be organized into the following categories:
Process Level Versus Subprocess Level The Common Elements
The Beginnings of Kaizen As stated earlier, Kaizen methods for work process improvement that include making the improvements originated in the World War II Job Methods training program. It was developed by the Training Within Industry (TWI) organization, a component of the U.S. War Manpower Commission during World War II. Kaizen methods that suggest improvements also originated in the work TWI. As suggestion rather than action improvement programs, Imai points out that, "Less well known is the fact that the suggestion system was brought to Japan...by TWI (Training Within Industry) and the U.S. Air Force" (1986, page 112). Huntzinger (2002) also traces Kaizen back to the Training Within Industry (TWI) program. TWI was established to maximize industrial productivity from 1940 through 1945. One of the improvement tools it developed, tested, and disseminated was labeled "How to Improve War Production Methods." It taught supervisors the skill of improving work processes. This program's name was changed to "How to Improve Job Methods" (War Production Board, 1945, page 191) and is most often referred to as Job Methods training. It taught supervisors how to uncover opportunities for improving work processes and implement improvements. It incorporated a job aid that reminded the person of the improvement process. This process began with recording the present method of operation including details about machine work, human work, and materials handling—much like a process observations would. It used challenging questions, to provoke the discovery of improvement opportunities. It provided tips for eliminating waste—e.g., discard unnecessary steps, combine steps where possible, simplify the operations, and improve sequencing. It incorporated operator involvement in identifying waste and developing better ways to do the process. It instructed people to check out their ideas with others, conclude the best way to make the improvement, document it, get authorization, and make the improvement. Its improvements included classic poka yoke solutions like the use of jigs and guides to reduce or eliminate errors. TWI emphasized incremental improvements focusing on the processes closest to the person and making improvements that did not require wholesale redesign of machines or tools. The linkage to Lean and Kaizen flows from the introduction of TWI into Japan by the U.S. occupying forces as a tool to rebuild Japan’s industry. The method was translated into Japanese, used extensively, and remained unmodified until 1955 (Kato, 2006).At that time Toyota commissioned Shigeo Shingo to upgrade the course with additional content. Shingo introduced more extensive time and motion measurement and analysis and renamed the course the "P-Course" (Kato, 2006). The "P-Course" replaced TWI's Job Methods training as Toyota's Kaizen training program and continued to be used until 1978 when Toyota again revised the program. Kato points out that Shingo also taught the upgraded Kaizen P-course at "...at Matsushita Electric Corporation and many other Japanese companies." By the time of the International Motor Vehicle Program's study of Japanese methods in 1985, Kaizen had been incorporated as a process improvement method in many Japanese companies for almost four decades.
Summary So, we can make these points.
Next Next, we will compare the purpose, benefits, contents, and methods of Six Sigma™ and Kaizen at the event (or project) level and Six Sigma™ and Lean at the business model level. Perhaps you can uncover some information about these topics and share what you discover. Use the Internet to do your research. Send what you find. Be sure to include the links to your sources. Also, send any comments you have about this article. We are always looking to expand our knowledge and understanding.
References Burns, Anthony D. (2007). Sick sigma, part 2. Available online at http://qualitydigest.com/IQedit/QDarticle_text.lasso?articleid=11905. Deming, W. Edwards (1982). Quality, Productivity and Competitive Position. M.I.T. Center for Advanced Engineering Study, Cambridge:MA. Deming, W. Edwards (1988). Quality and the Required Style of Management - The need for change. Journal for Quality and Participation in March, 1988. Available on line at: http://deming.eng.clemson.edu/pub/den/files/reqstyle.txt, viewed February 10, 2005. Huntzinger, Jim (2002). The roots of Lean. Training Within Industry: The origin of Kaizen. Association for Manufacturing Excellence, 18, No. 2. pages 9-22. Available on line at: http://www.tdo.org/twi/RootsofLean.pdf, viewed February 10, 2005. iSixSigma (2005). The History of Six Sigma™. Available on line at: http://www.isixsigma.com/library/content/c020815a.asp, viewed February 10, 2005. Imai, Masaaki (1986). Kaizen: The key to Japan’s competitive success. New York: McGraw-Hill Publishing Company. Japan Human Relations Association (1990). Kaizen Teian 2: Guiding Continuous Improvement Through Employee Suggestions. Portland, OR: Productivity Press. Joiner, Brian L. and Gaudard, Marie A. (1990). Variation, Management and W. Edwards Deming. Quality Progress, December 1990, pp. 29-37. Available on line at: http://deming.eng.clemson.edu/pub/den/files/varman.txt, viewed February 2, 2005. Juran, Joseph M. (1986). The quality trilogy. Quality Progress, August 1986, pp. 19-24. Juran, Joseph M. (1988). On quality planning. Wilton, CT: Juran Institute Inc. Kato, Isao (2006) Mr. Shigeo Shingo's P-Course and contributions to TPS . Available at http://www.superfactory.com/articles/Kato_Shingo.htm. Pecht, M. and Boulton, W.R. (1995) Quality Assurance and Reliability in the Japanese Electronics Industry. Available on line at: http://www.wtec.org/loyola/ep/c6s1.htm, viewed February 10, 2005. Pande, P.S.; Neuman, R.P.; and Cavanaugh, R.R. (2002). The six sigma way. New York, McGraw-Hill. Ramias, Alan The Mists of Six Sigma. BPTrends, 2005. Available online at: http://www.vitalentusa.com/pdf/TheMistofSixSigma.pdf, viewed October 29, 2007. Vitalo, Raphael L.; Bujak, Christopher J. ; Vitalo, Joseph P. ; Bierley, Patricia V. ; and Ruffino, Barbara J. (2007). Leading a business to high performance: The lean champion's resource guide. Lowrey Press, O'Fallon: MO (in press). War Production Board, Bureau of Training, Training Within Industry Service, September 1945, The Training Within Industry Report: 1940-1945, (Washington D.C.: U.S. Government Printing Office). Warren, Mark (2005) Personal communication. (Mark is managing partner with the Lean consulting company Tesla2, Inc.) Womack, James P.; Jones, Daniel T.; and Roos, Daniel (1991) The Machine That Changed the World. New York, NY: HarperCollins Publishers. Womack, James P. and Jones, Daniel T. (2003) Lean thinking. (Revised and Updated) New York, NY: Free Press. Wrona, R. (2005). TWI - The Missing Link to Continuous Improvement. Available on line at: http://www.tdo.org/twi/article1.asp, viewed February 2, 2005.
Footnotes 1A reviewer of this article cautioned me
to distinguish the Quality Model from the Quality departments that populate
businesses, since most readers will be familiar with the later and not the former.
Establishing a bureaucracy for “Quality” is inherently antithetical
to the Quality Model, as it tends to concentrate concern into one administrative
unit. The Quality Model is about involving everyone in owning and acting to
continuously improve. As well, most of these departments became repositories
for “standards” and data that is not shared and leveraged into better
performance. Finally, some of these departments remain essentially rooted on
post hoc discovery of defects, a practice denounced from the very earliest times
by Deming. Your Quality Department may be very different from this picture,
but if it is not, do not confuse it with what we refer to here as the “Quality
Model.”
Published March 2005; Revised November 2005; Revised October 2006; Revised and Rewritten November 2007; Revised July 2008
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