Evolution of Six Sigma

he Six Sigma methodology is not a revolutionary way of thinking, andit does not provide a radically new set of quality tools. It is more of anevolutionary development in the science of continuous improvement

that combines the best elements from many earlier quality initiatives.Although some of the tools used in Six Sigma, such as quality function deploy-ment (QFD), are relatively new, most, such as the fishbone diagram, date back50 years or more.

The philosophies related to Six Sigma have existed in one form or anothereven longer than that (see Figure 1). Customer focus, data driven decisionmaking, business results focus and process understanding are not newapproaches to business success. What is new, and what makes Six Sigma sopowerful, is the combination of these elements with a rigorous, disciplinedapproach and well-publicized, proven business successes.

General George Patton was a great student of history. He believed thosewho did not learn from past mistakes were doomed to repeat them. This istrue in the field of quality and continuous improvement, as well.Understanding qualitys roots and the reasons behind the methods will allowpractitioners to be better prepared to launch successful projects or large scaleinitiatives.

1798: Eli Whitney, Mass Production and Interchangeable Parts

Best known for his invention of the cotton gin in 1787, Eli Whitney had agreater impact on modern manufacturing with the introduction of his revo-lutionary uniformity system.1 In 1798, Whitney was awarded a governmentcontract to produce 10,000 muskets. He proved it was possible to produceinterchangeable parts that were similar enough in fit and function to allow forrandom selection of parts in the assembly of the muskets.

Throughout the next century, quality involved defining ways to objectivelyverify the new parts would match the original parts or design. Exact replica-tion was not always necessary, practical, cost effective or measurable.

Objective methods of measuring and assuring dimensional consistencyevolved in the mid-1800s with the introduction and use of go gages that veri-fied the minimum dimension of the new part.2 Correct replication of the max-imum dimension was assured by using the no go gages that were introducedabout 30 years later. Minimum and maximum tolerance limits, as measured bythe use of these gages, provided some of the first objective measures of simi-larity among parts. These measures eventually evolved into specifications. SeeFigure 2 (p. 41) for a list of some of the eras contributions to Six Sigma.

1913: Henry Ford and the Moving Assembly Line

With the introduction of Henry Fords moving automobile assembly line in1913, the need for predetermined part consistency became more acute. It was

H I S T O R Y

The Evolution of Six Sigma

A LOOK AT THE

INNOVATIONS THAT

CONTRIBUTED TO THE

METHODOLOGY WE

CALL SIX SIGMA AND

A GLIMPSE INTO ITS

FUTURE.

T

By Jim Folaron,

J.P. Morgan

Chase & Co.

38 I A U G U S T 2 0 0 3 I W W W . A S Q . O R G

The Evo lu t ion o f S ix S igma

critical that only good parts be available for use so theproduction assembly line would not be forced to slowdown or stop while a worker sorted through piles ofparts to find one that fit.

With the Industrial Revolution in full swing, everincreasing production volumes required differentmethods of testing and assurance to provide reason-able certainty the new product would be similar to theoriginal product or design. It was no longer practicalto test each piece against go and no go gages. Suchtesting was cost prohibitive, unacceptably time con-suming and, in some cases, impossible, especially ifthe test adversely affected the functionality of the out-put. Therefore, methods to monitor the consistencyof the process that produced the parts and the use ofsampling, rather than 100% inspection, were becom-ing necessities.

1924: Walter Shewhart

The Western Electric manufacturing plant inHawthorne, IL, is noteworthy because it was thebreeding ground for many quality leaders, includingJoseph M. Juran, W. Edwards Deming and Walter A.Shewhart. Juran worked at the plant for 17 years,Deming worked there as an intern during two sum-mers, and Shewhart worked in the research labs thatsupported the plant.

On May 16, 1924, Shewhart introduced a new datacollection, display and analysis form.3 It contained thefirst known example of a process control chart and sig-naled the beginning of the age of statistical qualitycontrol. The original control chart form allowed aninspector to document the percentage of defectiveproduct in both a tabular and a time ordered graphicformat. As data collection progressed, statistically

computed limits were drawn to identify the expectedrange of defective products. This helped alert theoperator to changes in the process.

The ability to use statistically based control chartschanged the role of the quality inspector from one ofidentifying and sorting defective product to one ofmonitoring the stability of the process and identifyingwhen it had changed. Early detection by the inspectoror worker helped identify the causes of the changeand target improvements. Improved product qualityresulted through planning and timely, appropriatecorrective action.

As production lots grew larger and more complexthroughout the remainder of the 1920s and 1930s, theneed for sophisticated quality assurance and controlgave birth to large quality control functions. Qualitycontrol departments came to include inspectors, chiefinspectors, supervisors, engineers and managers.4

The use of statistics grew, and in 1950, the U.S. gov-ernment required statistically based levels of productquality from its vendors. The military standard MIL-STD-105A was adopted and used by contracting offi-cers and purchasing agents to define contractuallyrequired sample sizes and maximum tolerable defectrates. This validated the need for large separate quali-ty functions. In reality, as quality evolved, it helped iso-late the responsibility for quality from the operatorsthat actually produced the product or service. Theits good enough or if its bad enough, the inspec-tors will sort it out mentality was common.

When World War II ended, consumer affluence inthe United States provided constantly increasingdemand. Fortunately, consumers had a tolerance formarginal quality. They readily absorbed the addition-al cost of inspection and sorting, thereby allowingmanufacturing operations to continue to focus on

S I X S I G M A F O R U M M A G A Z I N E I A U G U S T 2 0 0 3 I 39

Henry Fordsassembly line

Juranin Japan

1798 1840 1870

Eli WhitneyInterchangeable

parts

Go gages

No gogages

BritishStandards

Organization

1901

WalterShewhart

1945

WorldWar IIends

1950-54

Demingin Japan

1973

Oilembargo

PhilipCrosby

1980

ISO 9000MBNQA

QS-9000

19941987

Total qualitymanagement

Six Sigma

1913 1924

Figure 1. Developments That Led to the Current Six Sigma Methodology


volume and output without a need to focus on qualityimprovement or cost reduction.

1945: The Japanese Quality Movement Begins

Japan was crippled by the war. When it ended,General MacArthur and the occupying forces neededto help rebuild the communications infrastructure toinform the people of Japan the war had ended andthe United States was no longer an enemy.

Homer Sarasohn was summoned from theMassachusetts Institute of Technology to Japan toshare U.S. manufacturing management principleswith Japanese business leaders. Japanese leaders con-sidered the use of statistics the secret weapon thathelped the Allies win the war and wanted to learnmore about the practical application of this weapon.

Since Shewhart was too ill to travel in 1950, Deming,another learned statistician and friend of Shewhart,went to Japan to teach statistics and U.S. quality meth-ods. He reinforced the value of viewing data againstcomputed statistics to quantify variation and predictfuture process performance. This allowed timely iden-tification of the sources of problems and promotedthe opportunity for continuous improvement.

Throughout the years, Deming promoted the use ofthe plan-do-check-act (PDCA) cycle of continuousimprovement and later changed it to the plan-do-study-act or PDSA cycle.

The level of quality awareness and the use of statisti-cal methods grew rapidly, but the statisticians becameisolated and were seen as a separate layer of experts.5

Managers werent able to dedicate the time or effort tofully understand the statistical theories and applica-tions, and the operators were afraid of the statisticians,in part, because they feared measuring devices andautomatic recorders were being used to monitor theworkers performance. The operators also felt a lack ofcontrol over the changes being made.

The quality revolution was in jeopardy. In 1954,another American was invited to Japan to help addressthe problem.6 Juran brought his principles of qualitymanagement to Japan and helped integrate quality

initiatives throughout all layers in organizations. Hisconcept of integration was known as Big Q or quali-ty through managements active involvement andownership. Additional concepts introduced by Juranincluded the need for project by project qualityimprovement and the diagnostic/remedial journeys,all of which were documented in his Quality ControlHandbook, first published in 1951.

1973: The Japanese Make Their Move

Over the next 20 years, the efforts of the Japanese toconstantly improve quality and manufacturing capa-bility were more effective than those employed in theUnited States. Their focus on two aspects of produc-tivitydefect elimination and cycle time reductionresulted in many significant developments and suc-cesses for Toyota and other Japanese companies.Meanwhile, U.S. efforts focused on increased volumeand maintenance of a lucrative market share.

During the 1970s, one nonviolent event shook theworld and had a long-lasting, far-reaching impact onquality. The oil embargo of 1973 forced U.S. businessleaders to finally recognize the value of quality.Reduced supplies of oil products resulted in increasedcosts and long lines at the gas pumps.

The impact was even greater after the flow of oilresumed. The Japanese developed and brought tomarket more fuel efficient automobiles to address newcustomer requirements. These automobiles were lessexpensive, of higher quality and more closely satisfiedthe needs of the customer than those produceddomestically. The United States lost its market shareto foreign automobiles; the rippling effect of this lossproved significant.

1980: If Japan Can, Why Cant We?

If the oil embargo caused U.S. business leaders tobecome aware of the presence of foreign economiccompetition, the television documentary NBC airedon June 24, 1980, hit them over the head like a ton ofbricks.7 The documentary If Japan Can Why Cant


WHEN WORLD WAR II ENDED, CONSUMER AFFLUENCE IN THE UNITED STATES

PROVIDED CONSTANTLY INCREASING DEMAND. FORTUNATELY, CONSUMERS HAD A

TOLERANCE FOR MARGINAL QUALITY.


We? asked that very pointed question. Many people, including Ford Motor Co.s entire top

management team, went to visit the spotlighted U.S.company that improved significantly as a result ofDemings consulting work. The Nashua Corp. provedquality improvement was possible beyond the Japaneseculture.

With the renewed interest in his work, Deming begana new career at age 79, helping American managers bet-ter understand the concepts of variation and the valueof using statistical methods. He introduced many to anenlightened vision of quality using graphic displays (thered bead experiment) and easy to understand keypoints (his 14 point management theory and the sevendeadly diseases) during his four-day seminars.

Juran introduced a series of videotapes in 1979 enti-tled Juran on Quality Improvement and focused attentionon the quality trilogy (planning, improvement andcontrol) and the concept of project by projectimprovements. There were other teachers and topics:Armand Feigenbaum, Kaoru Ishakawa, Yoji Akao,Genichi Taguchi, Dorian Shainin and Shigeo Shingoare just a few of the leaders who came into the spot-light during this time. One other person who had theright message at the right time was Philip Crosby.

1980: Philip Crosby and Quality Is Free

U.S. industry was suffering through a recession andincreasing foreign competition when Crosbys book,Quality is Free,8 hit the market. He wrote about a 14-step approach to quality improvement and introducedmost of us to the concept of zero defects, which wasrooted in the U.S. space program. The book was seenby many managers as a surefire recipe for success.

Unfortunately, Crosbys roadmap did not alwayslead to the promised land. Quality was still too oftendelegated or treated as a separate initiative, and zerodefects seemed unattainable. As a result, many dis-missed the approach as unrealistic. It did, however,mobilize many people at all levels in organizationsand provided widespread information about qualitytools and their use.

1987: International Organization for Standardization

The desire for consistency in the definition of qual-ity led to the development of industrial standardiza-tion organizations beginning in Great Britain in 1901.By 1930, most of the worlds industrialized nationshad similar organizations. In 1987, the Geneva basedInternational Organization for Standardization,

known as ISO, introduced a series of quality standardsthat were adopted by most of the industrialized worldto serve as a single, global standard. Based primarilyon the BS-5750 quality system standard, ISO 9000detailed the key elements of sound quality practices.

These global standards were designed to promoteuniformity between countries that had their own defi-nition of quality specifications. This was most important


Figure 2. Each Eras Contributions to Six Sigma

1798: Eli Whitney, Mass Production and Interchangeable Parts

Need for consistency.

Identification of defects.

1924: Walter Shewhart

Process oriented thinking.

Control charts (assignable and common cause).

1945: The Japanese Quality Movement Begins

Statistical methods and use of statisticians.

Continuous improvement (plan-do-study-act)

methodology.

Active engagement of management and involvement

of everyone.

Diagnostic and remedial journeys.

1973: The Japanese Make Their Move

Quick responce to changing customer needs.

1980: Philip Crosby and Quality Is Free

Methodology to achieve companywide quality

improvement.

Improve product, process and service. Strive for

perfection.

1987: International Organization for Standardization

Widespread sharing of basic elements of sound

quality systems.

Organizational rally cry for improvement.

1987: Malcolm Baldrige National Quality Award

Sharing best practices.

Strong focus on customers and results.

1987: Motorola and Six Sigma

Focus on customer needs and comparison of process

performance to those needs.

Structured methodology with discipline and proven

business results.

1960-1995: Other Initiatives

Tools to be used by everyone in the organization.


in Europe where simultaneous purchasing from differ-ent countries could result in unplanned variation.

The other opportunity afforded by ISO 9000 was theability to force potential suppliers to submit to a third-party audit to confirm the existence of and adherenceto the quality standard. Third-party auditing and certi-fication was designed to provide reasonable assurancesof ongoing consistency to the purchaser and to mini-mize the number of site visits required by customers.

The creation of ISO 9000 helped define many of theelements of sound quality practice, but it did notassure the products goodness or fitness for use; it onlyaddressed consistency in the process. For example, acompany that sells cement lifejackets could be ISO9000 certified.

It was originally believed that within a few years, theEuropean market would close out any companies thatwere not ISO 9000 certified. Although this never cameto fruition, ISO 9000 served as a benchmark and pro-vided a marketing advantage, but it was not automati-cally exclusionary.

1987: Malcolm Baldrige National Quality Award

Throughout the 1980s, U.S. based manufacturingoperations continued to lose ground to constantlyimproving foreign competition, partially becauseJapanese firms believed in helping each other andsharing best practices with their countrymen. Then, in1987, the United States government introduced theMalcolm Baldrige National Quality Award.9 Thisaward is presented annually by the president and isdesigned to provide an operational definition of busi-ness excellence.

Two key aspects of the Baldrige Award are the pro-motion of best practice sharing and the establishmentof a benchmark for quality systems that focused oncustomer satisfaction as a primary driver of businessdesign and execution. Since then, the award has beenreplicated by many states.

The first company to win the Baldrige was Motorola.It recognized the need for focused quality improve-ment, and the award simply confirmed it had anapproach and deployment of metric based, customerfocused quality that would lead to the current SixSigma methodology.

1987: Motorola and Six Sigma

Motorola was greatly impacted by the qualityimprovements in foreign products. Under the leader-ship and support of Bob Galvin, the companys zeal

for quality improvement flourished. Stealing the bestpractices from the best companies (known as the ban-dit project10) was Motorolas attempt at turningaround the pocket pager business in the early 1980s.

Building upon these existing Motorola practices,Bill Smith and other Motorola executives married theconcept of process capability and product specifica-tions. Cp and Cpk measurements were used to com-pare the process performance to these specifications.The calculation for capability became defects per mil-lion opportunities (DPMO).

Both the DPMO and the use of specifications leftnaysayers with enough reason to dismiss the newapproach. They believed you could improve perform-ance by increasing the number of opportunities youconsider or by changing the specifications.Specifications were not directly based on customerneeds, rather they were often derived from productperformance data and typically reflected the capabili-ty of the process.

IBM and other companies that had adopted theconcepts of Six Sigma shared the new methodologyand philosophy with their suppliers, engineers andmanagers. To ensure widespread acceptance, thesecompanies and people needed to understand only thesignificant opportunities could be identified in theDPMO formula, and customers ever changing expec-tations must be considered. It was also important fororganizations to understand that embedding a com-panywide mindset of continuous improvement wasmore important than targeting a specific quality level,such as 3.4 DPMO.

1988: Beyond Motorola

As a result of winning the Baldrige Award in 1988,Motorola was compelled to share its quality practiceswith others. The companys approach to continuousimprovement was based on a comparison of processperformance and product specification, and aggres-sive efforts to drive down defects.

Eventually, the process was modified by others. Theoriginal measure, analyze, improve and control(MAIC) steps assumed the project had a clear defini-tion. IBM and other early users clearly identified theneed to ensure the project was properly scoped,resourced and defined by adding a D for define to themethodology (DMAIC). Other companies have sincemodified it even more. Some add an additional I toemphasize the need to implement the identified solu-tions; others include a trailing L to emphasize theneed to leverage the results across the organization.



AlliedSignal was one of the first companies to adoptand use the methodology. Larry Bossidy, AlliedSignalsCEO, demonstrated the business value of Six Sigma byeffectively turning around his company. In 1995, heintroduced the concept of Six Sigma to Jack Welch,CEO of General Electric. Welch took the methodology,made it a corporate requirement and firmly deployedit throughout his organization with great intensity andsignificant success. His results are well documented,and the rest is history.

1960-1995: Other Initiatives

The U.S. automobile industry, led by the Big Threeof Ford, General Motors and Chrysler, quickly recog-nized what a consolidated standard of quality coulddo, and QS-9000, the automotive supplier require-ments standard, was introduced in 1994.11 Compliancewith and certification against QS-9000 was a prerequi-site for vendors who wished to supply parts or servicesto one of the U.S. automakers.

The standard used ISO 9000 as a baseline, thenmade improvements, such as requiring an increaseduse of statistical process control, supplier manage-ment, failure mode and effects analysis and businessplanning. Besides these requirements, which aremandated by all three automakers, specific expecta-tions for each are also identified. QS-9000 requiresthird-party certification and a focus on continuousimprovement.

Various other quality initiatives became the flavor ofthe month in the time period from the 1960s to the1990s. Most made significant contributions to theadvancement of improved product or service quality,bottom-line impact or business redesign. But becausethey were not comprehensive, most failed to endurethe next consultant pitchman.

Quality circles, for example, were the an earlyJapanese import that failed miserably in the transla-tion. Observers in the United States saw small, volun-tary, empowered teams working on projects theyselected, but when the projects failed to produceimproved business results, they were abandoned as

not culturally transferable. Unfortunately, Americanobservers did not understand the real intent of quali-ty circles. The circles were originally designed to pro-vide foremen with small teams to lead during theirquality training. The teams served as just-in-time (JIT)opportunities to help the foremen practice what theywere taught. Reduced cycle times and inventory levelswere key elements of JIT manufacturing.

Likewise, kanban squares and pull systems were suc-cessfully developed and deployed in Japan. They werebrought here by Hewlett-Packard and popularized byRichard Schonberger.12 Many such concepts and prac-tices, including lean, have been absorbed by otherefforts that still exist today.

Another Japanese improvement method involveduse of j-cans, which involved structured, quickimprovement efforts that resulted in some improve-ment, though the results were of secondary impor-tance. The primary goal was to get practitioners tolearn problem solving tools and methodology.

Total quality management (TQM) was also popularfor a number of years. It began as total quality controlin the mid-1950s, was introduced in the HarvardBusiness Review by Armand V. Feigenbaum13 and wasdriven in Japan by Ishakawa. The first real attempt tosystematically deploy quality, TQM is still the term theJapanese use to describe their approach to quality.

TQM in the United States was a little different. Itinvolved banners and pride in quality, but it fell shorttwo ways:

1. It emphasized quality improvement for the sakeof quality improvement instead of tying improve-ments to the bottom line.

2. It focused on improvements within departmentsor business functions, not among them.

TQM introduced entire organizations to the bestquality tools and gave them the mindset to strive forcontinuous quality improvement, but because it didnthave significant dollar benefits, the movement did notendure.

Although many of these initiatives have come andgone, several of their elements are apparent in thecurrent Six Sigma methodology.


SIX SIGMA, WITH A FOCUS ON CONTINUOUS AND UNENDING

IMPROVEMENT, WILL ENDURE.


What the Future Holds

Will Six Sigma endure, or will it turn out to beanother flavor of the month? The coming years willbring changes and further improvements. Just as theworlds best sports car is not suitable for all personsand all situations, Six Sigma has an important, but notexclusive, place in the field of continuous improve-ment. But Six Sigma, with a focus on continuous andunending improvement, will endure.

There is, of course, an economic limit to theimprovement required, so the argument aboutwhether the goal should be 3.4 DPMO or zero defectsis not meaningful for more than a few companies.Both DMAIC and design for Six Sigma will have theirplace, but the rigorous nature of the methodology andthe time required to study and select options based ondata are not as significant for all improvements.

Although quick wins are allowed within the DMAICmethodology, management impatience requires moreflexible solutions, depending on the situation.Emergency response actions and interim containmentplans detailed in Fords global 8D program14 are twoexamples that serve different needs.

I believe Six Sigma will evolve significantly over thenext five to 10 years. Black Belts and Green Belts willnot exist as descriptors of specially trained profession-als. For a company to be successful, each person willhave to routinely use the tools and methods of rootcause identification and elimination. This lesson, orig-inally learned in the 1980s when large quality depart-ments were eliminated because they were detrimentalto the promotion of quality through employee com-mitment, will become a standard of good businessmanagement. The future will bring an even more rig-orous approach toward designing processes correctlythe first time rather than fixing existing processes.

We must be careful not to relive the problemsencountered by the Japanese. Ishikawa stated, It istrue that statistical methods are effective, but weoveremphasized their importance. As a result, peopleeither feared or disliked quality control as somethingvery difficult. We overeducated people by giving themsophisticated methods where, at that stage, simplemethods would have sufficed.15 Instead, we need toput the basic tools and the desire to continuouslyimprove into everyones hands, providing guidanceand support by skilled professionals and leadership bysenior management.

Maintaining a clear focus on customer wants andcontinuously improving the processes that provide theproduct or service will be the only way to remain com-

petitive. As the methodology reaches further into theeducational system, it will blend into the fabric of gen-erally accepted management practice. The future isbright, mostly because the past was so generous withlessons and success stories.

Though there will be changesthe certificationsand belts may go away, and Six Sigma training may beincorporated into other company training and lose itsidentitythe basic tenants will remain forever.Elements such as customer focus, data driven analysis,statistically based decisions, root cause problem iden-tification and elimination, process oriented thinking,process control to maintain improvements achievedduring the initial improvement efforts and sharing(leveraging) of results will always be necessary ele-ments of business success.

REFERENCES

1. Eli Whitney, http://technology.ksc.nasa.gov/ETEAM/whitney.html.

2. Walter A. Shewhart, Statistical Method From the Viewpoint of Quality Control,the Department of Agriculture, 1939.

3. Louis E. Schultz, Profiles in QualityLearning From the Masters, QualityResources, 1994.

4. Joseph M. Juran and A. Blanton Godfrey, Jurans Quality Handbook,McGraw-Hill, 1998.

5. Kaoru Ishikawa, What Is Total Quality Control? The Japanese Way, Prentiss-Hall, 1985.

6. Ibid.

7. Juran, Jurans Quality Handbook, see reference 4.

8. Philip B. Crosby, Quality Is FreeThe Art of Making Quality Certain,McGraw-Hill, 1979.

9. Malcolm Baldrige National Quality Award,www.nist.gov/public_affairs/factsheet/baldfaqs.htm.

10. Mikel Harry and Richard Schroeder, Six SigmaThe BreakthroughManagement Strategy Revolutionizing the Worlds Top Corporations, Doubleday,2000.

11. QS-9000 Quality System Requirements, AIAG,1994.

12. Richard Schonberger, Japanese Manufacturing Techniques: Nine HiddenLessons in Simplicity, Free Press, 1982.

13. Armand V. Feigenbaum, Total Quality Control, McGraw-Hill, 1953.

14. Abdul Chowdhry, To Be a Problem Solver, Be a Classicist, QualityProgress, June 1999.

15. Ishikawa, What Is Total Quality Control? The Japanese Way, see reference 5.

Note: This article is not a complete listing of the many innova-

tors, teachers or practitioners who have guided us in the develop-

ment of improved quality tools and methodologies, nor does it

detail the many contributions of those who are included.


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Evolution of Six Sigma