WHAT WILL SIX SIGMA LOOK LIKE IN FUTURE

Six Sigma is a disciplined data-oriented approach to quality improvement that will survive and flourish. However, as it continues to evolve, some of its concepts—such as 3.4 defects per million opportunities—will be modified. Other characteristics of Six Sigma, such as its hierarchal organizational structure, will be adapted to changes in the environment. We will also continue to benefit from lessons learned1. Overall, Six Sigma will cast a continuingly broader net, but, will likely, be less in the headlines.

Key Concepts that Will Survive and Flourish

Six Sigma calls for a disciplined customer-focused approach to quality improvement, resting on the principle “In God we trust, all else bring data.” These basic concepts will be as important in the future as they are today. Here’s why.

Global competition and customer demands will continue to call for continuous quality improvement, coupled with cost reduction. Thus the pressures that lead to Six Sigma in the first place are unlikely to abate, and may even increase.

A disciplined and proactive approach to quality improvement that puts the customer first continues to make great sense and helps ensure that we move forward in an organized manner. The specific approach may vary from one situation to the next. DMAIC (define, measure, analyze, improve, control) was appropriate for the typical manufacturing applications for which Six Sigma was originally proposed. DMADOV (define, measure, analyze, design, optimize and verify) was subsequently proposed for Design for Six Sigma. Other approaches may be appropriate for other application areas. Necip Doganaksoy and I have, for example, recently proposed DEUPM (define, evaluate, understand, plan and monitor) as a disciplined approach for data acquisition2.

The need to base decisions on data, rather than on hunches, has always been there. What has changed in recent years—and has helped make Six Sigma a reality—is our ability to collect, harness and rapidly bring to bear such data in the decision-making process. We, no longer, need to rely on statisticians to do the work. Instead, Six Sigma practitioners are empowered to proceed on their own—calling on statisticians for guidance on the more complex issues. This trend is likely to accelerate. As technology continues to develop, so will our capabilities to use data to make the right decisions to improve quality. We can expect, for example, greater emphasis on the all-important task of getting the right data and more focus on meaningful and simple ways of presenting results graphically.

A Concept that May be Modified: The Goal of 3.4 Defects per Million Opportunities

Six Sigma has been presented as a drive to achieve “no more than 3.4 defects per million opportunities.” That, of course, is the basis for the terminology (with a little juggling to take into account the claimed mean shift of 1.5 sigma in moving from short-term to long-term variability). As quality practitioners become savvier, they recognize that this objective has its limitations.

As Deming pointed out repeatedly3, setting numerical goals can often lead to a search for ways to manipulate the measurement process, rather than improve the system. This is especially so when one is dealing with often vaguely defined terms, such as “defects” and “opportunities.” There is, indeed, frequently much subjectivity in deciding exactly what is a defect and, even more so, an opportunity.

All products, moreover, are not created equal. There are many more defect opportunities for a jet engine than for, say, a toaster. But, yet, the need for high reliability for a jet engine is generally greater. For a toaster, aiming for 3.4 defects per million opportunities might be overkill, or just too expensive. This level, on the other hand, may be fully appropriate for a jet engine.

Despite Deming’s warnings, we will continue to need numerical goals. But these will be tailored to the product at hand and closely tied to customer needs. For example, for a telephone-servicing center, a clear goal might be that of keeping the time that a customer has to wait for service to less than one minute 95% of the time and to less than three minutes 99% of the time.

The prediction that we will move away from the concept of 3.4 defects per million opportunities defies classical Six Sigma thinking and is, surely, controversial. I welcome other viewpoints.

Simplification of the Hierarchal Structure

Six Sigma came with a formal organizational structure of champions, master black belts, black belts, and green belts—each with designated responsibilities. As Six Sigma approaches its goal of becoming “the way we work,” this formal structure will be modified. Thus, as the value of Six Sigma is recognized universally, all managers will, ideally, be Six Sigma advocates, reducing the need for special champions. Master black belts will continue to serve as trainers, hands-on advocates and gurus—but their role may be merged with that of black belts. Also, master black belt status will increasingly be a stepping-stone to management. As Six Sigma training becomes commonplace both within companies and in universities, all professional employees will be green belts (even if not always identified as such). This, in fact, has been the situation in GE for some time. The Six Sigma organizational structure, like other parts of the organization, will, in addition, not be immune from cost-cutting pressures.

Casting a Continuingly Broader Net

Six Sigma will be enriched by the continued emergence of useful tools, such as simulation, that may not have been part of the original toolkit, but whose value has been demonstrated. It will also gain from integration with other approaches, such as lean thinking.

The areas of application for Six Sigma will continue to multiply. Early uses of Six Sigma tended to be mainly in product manufacturing. This provided relatively speedy and easy-to-quantify paybacks. It was soon recognized, however, that only so much can be achieved in manufacturing, and that product performance and reliability are principally determined at product design. This led to Design for Six Sigma and Design for Reliability. Next, Six Sigma was applied to business processes and customer service. As we move away from manufacturing applications, our ability to quantify the benefits of Six Sigma becomes more complicated. It is harder to measure the impact of avoiding a field failure or of having a delighted customer, than, say, that of a 90% reduction in scrap. This trend will continue as we seek new applications. We need to recognize and address the associated challenges.
Most of the applications of Six Sigma to date have been in large companies. In the future, Six Sigma will be adapted for use in small business with limited resources. Also, we are beginning to witness its application in areas other than manufacturing businesses, especially in the medical arena. Similar opportunities exist and will be leveraged in future years in such diverse fields as banking, schools, and government.