On ASQ' s website, you can find two similar definitions of Six Sigma. Under Training and Certification, it's defined as a "method for reducing variation in manufacturing, service or other business processes. Six Sigma projects measure the cost benefit of improving processes that are producing substandard products or services."¹

The Quality Progress glossary says Six Sigma is a "methodology that provides businesses with the tools to improve the capability of their business processes. This increase in performance and decrease in process variation leads to defect reduction and improvement in profits, employee morale and quality of product."²

Of course, any definition at the level of these two examples fails to be sufficiently descriptive to enable a careful analysis of what is missing or what needs to be enhanced in Six Sigma. Furthermore, the real problem of description is, of course, that in practice the definition of Six Sigma is different for every organization using the methodology. Hence, any statements I make about what Six Sigma lacks may fail to be universally applicable. Some readers will react by noting their organizations' implementation of Six Sigma includes things I say are missing.

My response is, "Good work, bravo - and please call or e-mail me about your experiences. I'd love to hear about them. I don't doubt you, but my observation is that your experience is not typical."

In this article I am ultimately looking at what Six Sigma training programs and the tool sets of Black Belts (BBs) and Green Belts (GBs) lack in two ways - from the standpoint not only of what exists in formal definitions and published reports but also from my own experiences and discussions with practitioners.

I categorize those things missing from Six Sigma into three major groups:

1. Technical but not statistical.
2. Nontechnical.
3. Statistical.

Technical But Not Statistical

Four important things are missing or used insufficiently in the technical, nonstatistical area:

1. Financial analysis.
2. Theory of constraints.
3. Concepts and tools of lean.
4. Simulation.

Financial analysis. Financial analysis, specifically the ability to do a precise and careful analysis of a project using the concepts of net present value (NPV) and internal rate of return (IRR), is a skill in short supply for many BBs.

I have seen too many BB projects in which the financial analysis was at the level of the classic but badly flawed payback period method, which totally ignores the time value of money. Surely, given the underlying themes of Six Sigma, its advocates do not want to advertise they are ignorant of the time value of money.

The difference between NPV or IRR and the payback period analysis can be substantial, especially when the cash flows span several years. The ASQ Six Sigma body of knowledge (BoK) does include the concepts of NPV and return on investment, although this appears to be absent from the Six Sigma curricula of several well-known consulting companies and other organizations using Six Sigma.

In addition, more than a few BBs with whom I have worked had not known how to do simple analysis to determine the NPV of a project, even with the use of capabilities common in well-known spreadsheet software.

One BB said until recently he had never seen NPV until he learned about it outside the context of Six Sigma, several years after his BB certification. He added, "My company does a weak payback period report at best."

The ability to perform financial analysis of a project via NPV and IRR should be a fundamental tool - a basic competence - for a project oriented methodology such as Six Sigma.

Theory of constraints. There is a brief mention of the theory of constraints (TOC) in the ASQ Six Sigma BoK - at the concept level.

TOC is a set of tools that examines the entire system for continuous improvement. The tool set includes the current reality tree, conflict resolution diagram, future reality tree, prerequisite tree and transition tree.

I would like to see more about TOC. Specifically, the thinking processes developed by Eliyahu Goldratt are superb and should be a part of the portfolio of every BB or GB.³

Lean. On a closely related subject, I am extremely pleased to see the presence of a sampling of the concepts and tools of lean in the ASQ Six Sigma BoK and to observe the rapidly increasing tendency over the last few years to include a significant portion of such material in BB and GB training. I am hopeful this trend will continue.

Transforming from batch production to lean using the tools of one-piece flow, cellular layout, setup reduction, mistake proofing and kanban, to mention but a few of the key concepts of lean, is a major vehicle for operational transformation.

The BBs and GBs should be part of these efforts, contributing with lean related knowledge and the other tools of Six Sigma for variability reduction. Reduction of variability is frequently a critical part of a lean transformation.

If the content is not included in the curriculum for BBs and GBs, separation of the Six Sigma efforts from lean transformation efforts is likely and definitely not in the interests of the future growth and prosperity of Six Sigma.

When I have been a part of Six Sigma training, I have noted a great many initial projects have focused on applying the concepts and tools of lean. Sadly, I have seen a sampling of other organizations in which the Six Sigma and lean activities are practically disjointed - even competing for resources and attention.

Simulation. More than a few MBBs and BBs with whom I have spoken indicated they thought their organizations would be better off if their BBs had a better knowledge of the power and application of simulation. Closely related to this, Six Sigma development should include a good exposure to sensitivity analysis. Practitioners of Six Sigma should be quite aware of the degree to which their recommendations depend on their assumptions - and both simulation and sensitivity analysis can help them explore this. In addition, simulation can be a powerful tool for exploring the consequences for the flow of changes in line design.

Nontechnical

Nontechnical aspects I deem not practiced sufficiently in Six Sigma include:

• The soft side of change management.
• Performance based management.
• Customer satisfaction measurement.
• Selection, training and management of BBs.
• Broader criteria for project selection.
• Use of design for Six Sigma.

The soft side of change management. It just doesn't seem possible to include enough about the soft, or nontechnical, side of change management. Repeatedly, postmortems on less than fully successful Six Sigma projects reveal the point of failure was not a lack of sufficient statistical methodology or an inability to create a project timeline.

Instead, projects ran aground because the project team leader failed to manage the internal (and sometimes external) stakeholders and ran afoul of opposition, which either delayed or actually derailed implementation.

Do typical Six Sigma training programs cover such content? Typically yes, but the results I've seen make it clear further help, perhaps provided by more intense real-time coaching in this area, is needed to improve the success rate for projects. Individual organizations - or Six Sigma consultants - could examine their own implementation track records to diagnose whether their Six Sigma curricula need major strengthening in this area. (We, of course, assume Six Sigma professionals keep good data on the success of projects in terms of percentage succeeding and impact. Most I have worked with do.)

Performance based management. Another BB who reviewed this article urged me to stress the need for extensive knowledge of the methods of performance based management. A brief discussion of measurement, incentives and typical dysfunctional behaviors induced by measurement is clearly not sufficient - this is information known broadly for more than a half century. Good measurement system content and properly aligned objectives and behaviors to those systems are critical.

Customer satisfaction measurement. A few years ago, authors of an article in Quality Engineering discussed several things that should grow in the Six Sigma content package, including a focus on customer satisfaction.⁴ Familiarity with state-of-the-art methods for measuring customer satisfaction should be a requirement for BBs.

Broadening beyond even this, one BB who reviewed a draft of this article told me, "Determining and understanding the voice of the customer is a skill which should be understood and applied."

Selection and management of BBs. BB candidates should have balanced skills. Strong analytical skills are of course important, as are good people skills. Some organizations report having to work hard to get an appropriate male-female balance among BBs. Others have noted struggling to get people with the ability to see and understand the big picture as well as ones who are good at detail.

Broadly speaking, organizations need to work carefully and hard to balance the actual skill and personality mixes of BB candidates against their needs.

Roughly 20 years into Six Sigma's being practiced under that name, organizations still report difficulty developing career paths for BBs. Too often, those with a good track record at successful project management move on to similar jobs at different organizations because there simply aren't enough potential MBB jobs to have that be a credible next step.

If an organization has a sincere desire to capture fast-track managers earlier in their careers for involvement as BBs, it should build and make visible a path for transition back into an appropriate management track at an appropriate level at the conclusion of a tour of duty as a BB.

One BB I discussed this with said, "Mentoring and championing would also benefit this reintegrating BB. All too often the fate of the BB is left to his or her own wit and resourcefulness."

Broader criteria for project selection. The so-called bounty criterion (often operationalized by requiring a BB candidate to complete an ensemble of projects with a total payback of at least a certain dollar amount) has often encouraged an overemphasis on projects aimed at cost cutting. This is because the gains from cost cutting projects are often easier to document and faster to manifest themselves than are the gains from growth driven projects.

This has led to less emphasis on projects related to business size or other strategic business objectives - which usually take longer to accomplish than those with cost cutting as their target. General Electric MBBs have told me they found it necessary to strongly encourage BBs to emphasize growth as an objective of at least some projects.

One BB at another organization told me, "Management fails to understand selection and prioritization of projects. Project selection is often a stream of consciousness effort with no business strategy considered or alignment of business strategies checked. There are many projects pointing in many directions. Often there is no management authority to ensure all projects are pointed at the overall tactical business plans." Clearly, stronger mentoring by MBBs would help in this situation.

Michael Hammer wisely pointed out too many Six Sigma projects have been "so narrowly focused, concentrating on low level and small scale activities, typically within one functional unit of the organization."⁵ This is a fair comment, although it is of course not representative of all Six Sigma implementations or all Six Sigma projects.

The portfolio of Six Sigma projects in an organization should include a full range of efforts, from fullscale attacks on the major processes of high strategic importance to smaller projects that can be completed in shorter timeframes.

As Six Sigma philosophy becomes more of "how we do business every day," this range will become even more important - and more feasible.

Design for Six Sigma. The emphasis on design for Six Sigma (DFSS) should grow over time, as Six Sigma matures in an organization.6 DFSS is a data driven strategy for designing products. To increase its use, organizations should either continue or start to include some familiarity with DFSS in their BB training.

Statistical

Missing BB statistical knowledge frequently includes:

• Core concepts of reliability.
• Data mining tools.
• Sample surveys.
• Forecasting.
• Use of graphical methods to present statistical data.

Core concepts of reliability. In some situations, vital content is missing, but I would be hard pressed to maintain it is part of what every BB ought to know. Examples include reliability, particularly design for reliability.

A set of core concepts of reliability certainly ought to be a part of the repertoire of any BB. However, the specific appropriate detailed methodology and its extent would be very different in the banking and financial industry and the semiconductor industry.

Whether detailed methods for life testing - accelerated or otherwise - or design for reliability or another method are most appropriate depends on the applications, of course.

Data mining. The tools of data mining, broadly conceived, do not necessarily belong in the "what every BB ought to know" category. Clearly, however, many organizations would benefit greatly from having BBs with data mining experience. It seems to me few BBs have learned about the method from sources related to their Six Sigma development.

Sample surveys. Learning more about sample surveys - the management side as well as the mathematical side - would be an improvement in BB training. Sample surveys are not that uncommon in being required as part of a Six Sigma project - whether as part of a voice of the customer exercise, as a way of assessing progress or for some other purpose. Sadly, this is a subject in a state of neglect in far too many academic statistics departments, and therefore the competence is unlikely to be acquired there. It needs to be built into Six Sigma training.

Forecasting. I would also like to encourage organizations to at least consider whether an introduction to the methods of forecasting would be appropriately and highly leveraged for a subset of their BBs. Even if only simple methods of single and double smoothing plus some autoregressive methods and some of the typical modifications for seasonal data are covered, this will be a substantial contribution.

Use of graphical methods to present statistical data. I wonder whether others have had experiences similar to mine - reviewing Six Sigma projects that had plenty of screen shots about outputs but left the audience starving for a graphical display to illustrate what was learned from the data.

My review of a variety of Six Sigma training materials does not suggest there is a need to spend more time learning how to present data graphically, but I do believe a greater emphasis on actually using these methods to present statistical data would be helpful.

Ominous Trends

In the early years of Six Sigma, developers of GBs and BBs had considerable experience improving processes using both statistical and nonstatistical methods. My observation has been that as demand increased, the need to expand capacity for development of BBs led to a weakening or dilution of the talent pool of the developers and trainers.

This trend is not a good one and can be addressed only if organizations insist those they are paying to develop BBs and GBs have more substantial experience. Customer organizations should ask trainers focused questions about the amount of experience with actual Six Sigma projects they - not merely the organizations they represent - have.

Another ominous trend could, if it continues, lead to further shortcomings in the Six Sigma BoK. As the number of training providers has grown and competition has increased in the field of Six Sigma consulting, the natural pressure on the consulting companies has led to an unfortunate tendency to cut corners on the BoK they attempt to deliver.

In too many cases, those doing the training have shortened the BB training and mentoring process. This is unfortunate. Consulting companies would do well to refer back to the ASQ BoK for Six Sigma, and their customers would do well to insist on maintaining at least that minimal content level, not shortening the training and mentoring process to cut expenses and speed it up.

Doing this is neither simple nor unimportant because we are dealing with elemental economic forces here.

In the absence of significantly greater work to counter the existing trends, eventually the phenomenon of customers unable to discern technical content will lead to a continuation of the trend to thin down the content in Six Sigma training, with the result being BBs and GBs with less and less capability with every passing generation.

This will eventually happen unless customers can become more discerning and consultants more assertive and skillful in guiding their customers in this important area.

An anecdote illustrates the need for some sort of broadly acknowledged standards related to the development and training of BBs. One BB to whom I showed an early draft of this article said the following:

Could there be some level of certification for legitimate training courses? I had a guy who was looking at one of my projects call me on the phone a couple of months ago. He claimed he was an MBB. When I asked where he trained, he said he did it online with no real-time mentoring. He added he would soon be a "lean master," or sensei. I couldn't believe it. He was serious. There should be some way to stop these online bandits. They really bring a bad reputation to all practitioners. Ultimately, it is the responsibility of the customer to verify credentials, but quite frankly many customers have no ability to differentiate.

Six Sigma has been successfu l- wonderfully successful - in serving as an action oriented method for improving processes to yield better financial outcomes. Only through continual improvement - a basic principle of quality - will it remain a viable and lasting methodology.

 

ACKNOWLEDGEMENT
The author thanks Donald L. Blackburn, Lloyd Jollay and Barry Totten, who reviewed this article prior to submission.

REFERENCES

1. ASQ Training and Certification,
   www.asq.org/certification/faq/17.html.
2. Glossary, www.asq.org/glossary/s.html.
3. Eliyahu M. Goldratt and Jeff Cox, The Goal, second revised edition, North River Press Publishing, 1992.
4. Gerald J. Hahn, Necip Doganaksoy and Roger L. Hoerl, "The Evolution of Six Sigma," Quality Engineering, Vol. 12, 2000, pp. 317-326.
5. Michael Hammer, "Process Management and the Future of Six Sigma," Sloan Management Review, Winter 2002, pp. 26-32.
6. Ronald D. Snee and Roger W. Hoerl, Leading Six Sigma: A Step-by-Step Guide Based on Experience with GE and Other Six Sigma Companies, Financial Times/Prentice-Hall, 2003.

The author is Professor of Decision Sciences at CEIBS.
Reprinted with permission from Six Sigma Forum Magazine
© 2006 American Society for Quality.