Six Sigma DMAIC and DMADV FAQs (Frequently Asked Questions)

 

Glossary of Six Sigma Terms

 

What is Six Sigma?

Six Sigma is a complete program for addressing how well your organization meets customer and stakeholder requirements. To achieve performance excellence it identifies process variations and systematically works toward managing those variations in order to eliminate defects and deliver high performance, reliability, and value to the end customer.

First developed at Motorola in the 1980s, Six Sigma was originally defined as a metric for measuring defects and improving quality, and a methodology to reduce defect levels below 3.4 defects per million opportunities (DPMO). However, Six Sigma has grown beyond mere defect control to become a proven methodology for achieving overall performance excellence.
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How does Six Sigma differ from past management initiatives?

Past initiatives contain a great deal that is useful, but they usually fail for specific reasons, including:

  • Lack of executive leadership. Management fails to demonstrate its commitment through deeds. Successes are won by innovative mid-level managers, but matters soon grind to a halt without active leadership from the top.
  • Failure to deploy. Good results are initially obtained through launch enthusiasm and mentored training, but no process is embedded to keep the efforts going or expand them into other departments.
  • Seeking shortcuts. Successful pioneer companies develop programs over the long term that incorporate many interlocking elements. Success inspires imitation, but the next generation of companies often tries to emulate the success without the hard work. They may adopt only some elements of the successful pioneer program (or even only the name) hoping for instant success.
  • Inadequate measurement. In some initiatives, there is no way to properly measure status or progress. It’s not that there are no measures (in fact, the organization is often overmeasured), but rather that the measures may not relate properly to business results or to the strategic business plan.
  • Incompleteness. Some past initiatives addressed only one facet of a total program: tools without goals (SPC), goals without tools (ZD), philosophies without infrastructure (TQM), infrastructure without action (ISO 9001), measures without tactics (MBO), and so on.

Six Sigma incorporates the successful elements of past initiatives and adds a lot more. There is a measure—sigma performance—that evaluates processes based on their ability to meet customer requirements. There are strategies for all three phases of management—process (re)design, process management, and process improvement. Finally, there are toolkits of tactics and qualitative and quantitative methods for each strategy. All of these combine to produce streamlined processes and performance excellence.

What exactly is sigma performance?

Sigma performance measures process performance relative to customer requirements. It takes into account some degree of undetected, nonrandom variation (“shift”). Unlike the capability index, all qualities, both measurable and countable, can be combined into a single scorecard.

Sigma can be normed to the complexity of the process using defects per million opportunities (DPMO) to facilitate comparisons across different processes.
 

What is the goal of Six Sigma

The goal is for an organization to achieve strength by moving progressively toward a sigma performance level of 6. At this level, the process is robust against undetected process shifts; that is, variation is small enough relative to the requirements that a shift will not result in more than a few defects in a million opportunities.

Doesn't "sigma" referred to the standard deviation of data.

It does, and for measurable data, sigma performance is directly related to the standard deviation. The two uses of the term "sigma" should not, however, be confused.

What is the Six Sigma approach to quality management?

Defects and errors occur because of the collision between what we must do (customer requirements) and what we can do (process capabilities). Six Sigma works to minimize the difference between what your customers need, and the product or service you deliver. It does so using three fundamental strategies: process management, process improvement, and process (re)design. All three strategies must be used to gain the full benefit of Six Sigma

What is process management?

Process management identifies and controls the key input and process variables (X’s) to achieve acceptable outputs (Y’s). It detects and corrects adverse changes by fixing what went wrong. The strategy for this phase is called PDCA (Plan, Do, Check, Act).
Many organizations do a fair job of process management and often achieve a sigma performance level of 4; however, achieving a higher sigma performance level requires process improvement or process (re)design..

What is process improvement?

Process improvement identifies and changes the input or process variables (X’s) that account for persistent normal performance to achieve a sustained higher level of performance (Y’s). It creates beneficial changes by improving those elements that can be made more efficient. The strategy for this phase is called  DMAIC (DEFINE, MEASURE, ANALYZE, IMPROVE, and CONTROL).

What is process (re)design?

Process (re)design identifies the key input or process variables (X’s) that enable new or significantly modified processes to meet customer requirements (Y’s) as soon as they are employed. The strategy for this phase is called DMADV (DEFINE, MEASURE, ANALYZE, DESIGN, and VERIFY).

What is PDCA

PDCA is used to manage a process. The acronym stands for:

  • Plan the process management system: Link your daily work to your business strategy and customers' requirements; determine and document the best steps for completing the work, what will be checked, how, how often, etc.

  • Do the actions specified in the plan.

  • Check actual performance against the process management plan (PMP): Measure and review process outcomes (Y's) and key input and process variables (X's) on a regular, timely basis.

  • Act when there is a gap between the "should-be" of do and the "as-is" of plan. This may require normal control activities to identify and fix what went wrong; but it may lead to a decision to initiate a DMAIC improvement project.

This systematic process management methodology ensures that processes are maintained at the best performance level achievable, given the present design of the process.

What is DMAIC?

DMAIC is used to improve a process. The acronym stands for:

  • DEFINE the problem and the process involved, then align them with customer needs, wants, and expectations.

  • MEASURE the current process performance from many points of view in order to pinpoint the problem.

  • ANALYZE to determine and verify the root cause of the pinpointed problem.
    • IMPROVE by implementing countermeasures that address the problem’s
    root causes. If this requires significant redesign, we link to the appropriate step      DMADV.

  • CONTROL to maintain the gains. This links to the Plan step of process management.

This systematic process improvement methodology ensures that the root causes of chronically poor process performance are identified and addressed so as to achieve a sustained improved level of performance. Improvement actions may lead to significant redesign of the process.

What is DMADV?

DMADV is used to (re)design a process. The acronym stands for

  • DEFINE the opportunity, project plans, risk assessments, etc.

  • MEASURE and determine customer needs, wants, and expectations.

  • ANALYZE the design options to select the approach that best addresses customer needs, wants, and expectations.

  • DESIGN the process by selecting design elements and specifying the details. Cascade the customer requirements to system, subsystem and element levels and compare these to available capabilities.

  • VERIFY the design performance.

This systematic design methodology can build processes that will reliably meet customer expectations. It can be used when DMAIC leads to significant redesign or when a new product, service, or process is being considered.

How do these three strategies link together?

The Act step of PDCA may lead to a decision to initiate a DMAIC improvement project when the problem is not a departure from normal performance but the normal performance itself.

The CONTROL step of DMAIC links to the PLAN step of process management to incorporate the changes into the process management plan.

The VERIFY step of DMADV links to the PLAN step of process management to incorporate the new product or process into the process management plan.

The ANALYZE or DESIGN steps of DMADV may lead to a decision to initiate a DMAIC improvement project if the available process capabilities cannot meet the requirements at that design stage.

What is DFSS? How does it fit with my organization?

Design for Six Sigma (DFSS) is the goal of the process (re)design strategy (DMADV). It means that we set out to create a design that is Six Sigma capable. This involves a trade-off between the top-down cascade of design requirements (from customer to system to subsystem to design element) and the bottom-up stacking of process capabilities (from element to subsystem to system to customer). The DFSS objective is to balance this trade-off using transfer equations that relate the X’s at the lower level to the Y’s at the higher level, and then either adjust the allocation of requirements or improve the process capabilities.

Should my organization pursue Six Sigma, Lean Enterprise, or ISO 9001?

It is not an either/or proposition—these programs are complementary, and your organization should be pursuing all three in order to achieve optimal performance.

  • Six Sigma is a model for designing, managing, and improving process results. It focuses on the effectiveness or accuracy of the process.

  • Lean Enterprise is a model for designing, managing, and improving process flow. It focuses on the efficiency or speed of the process.

  • ISO 9001 is a model for quality management systems. It provides a foundation for process management by helping to define the processes needed to obtain the planned results.

How do Six Sigma and Lean interact?

Improving process accuracy through Six Sigma improves the flow, because there will be less rework and correction. Additionally, Lean strategies—such as eradication of non-value-adding work or simplification—will improve the results by eliminating both opportunities for error and the complexities that lead to error.

What would it take for us to implement Six Sigma?

There are seven essential steps to implementing Six Sigma.

  1. Top management understanding the necessity of Six Sigma and making the commitment to implement it successfully.

  2. Access to current information on customer needs—your critical data pool.

  3. A process management system to measure current performance and identify where you need to make improvements.

  4. Resources—Black Belts and Green Belts—trained to design and improve processes and to assist process owners.

  5. Ongoing management involvement and review to reinforce process management, improvement, and design.

  6. Communication to ensure that customer focus and Six Sigma methods are embraced throughout the organization.

  7. Assigned responsibilities for Six Sigma within the organization.
     

How long does it take the Six Sigma management philosophies to become established in an organization?

It can take anywhere from two to five years for Six Sigma management philosophies to become completely established in an organization—there are no shortcuts. Progress depends on how well top management leads the initiative. If top management is out front leading the effort by both encouragement and example, then Six Sigma will permeate the organization more quickly and more permanently.

How can Oriel Incorporated help?

Oriel Incorporated provides analysis, training, and implementation support for Six Sigma. Skilled consultants diagnose where process change would most benefit your organization. Then, attuned to your needs and culture, they apply the strategies calculated to produce rapid and profitable results. Oriel Incorporated consultants work with senior managers and organizational leaders to develop a plan, involving personnel who manage and work in the targeted process. These steps give your organization’s leadership the expertise necessary to create and sustain improved sigma levels and achieve success..

What is a Black Belt?

A Black Belt is an individual who has sufficient expertise in DMAIC and DMADV to lead a major improvement or (re)design project.

What is required to become a Black Belt?

  1. The organization ensures that the candidate possesses the personal skills, leadership prowess, and experience to lead project teams.
  2. The candidate attends an intensive four- or five-week training program; the four
    week-long sessions are spaced about a month apart. The candidate must pass a written
    examination at the end of each session and after all four sessions have been completed.
  3. The candidate leads, from inception to conclusion, a successful Six Sigma project that has been authorized and validated by the organization, and submits a report to the examiner. This report must demonstrate the candidate’s mastery of the tools and methods of Six Sigma. Any tools not required by the project itself can be demonstrated by means of separate case studies conducted and reported by the candidate.

Do I have to be a statistician to become a Black Belt?

No—our Black Belt course teaches you the all the statistical tools you’ll need to use. We also teach you how to operate the statistical software, MINITAB, which will help you apply statistical analyses to the data you collect.

How will I know when to use the statistical tools?

Our Black Belt training teaches you when to use the statistical tools and how to interpret the results throughout the entire DMAIC problem-solving process.

Is a full time Black Belt better equipped than a part time Black Belt?

Yes. In the competition for people’s time, the full-time job always wins over part-time assignments, so the Six Sigma projects must become the Black Belt’s full-time responsibility for the duration of the project. Organizations have learned that Black Belts are more successful when they are relieved of all or most of their regular duties, allowing them to focus more intently on their improvement or (re)design projects. A Black Belt may work on more than one project at a time.

What is a Green Belt?

Green Belts are individuals who have sufficient expertise in DMAIC or DMADV to contribute to a major improvement or (re)design project through data collection, analysis, and other activities. Although they typically perform in a supplementary role, they may sometimes lead smaller scale improvement projects.

What is required to become a Green Belt?

This will vary from company to company. Candidates take a one- or two-week training class and pass a written examination. Project work is normally assigned and evaluated by the organization itself.

Why should my organiazation focus on improving sigma?

The Six Sigma approach is about reducing variation in processes so that you can consistently meet customer needs. The benefits to improving sigma include:

  • Lower costs

  • Enhanced resource use

  • New ideas

  • Increased job satisfaction

  • Increased profitability

How do I know which processes my organization should target for improvement?

Not every process needs immediate improvement. Start by considering which processes concern your customers the most and place your priorities there. For example, a grocery chain might learn from surveys that their customers care less about how many varieties of tomatoes are for sale than they do about how those tomatoes are grown and how safely they are processed.

How do I select Six Sigma projects to undertake?

There is a systematic process for selection. It begins with top management, who list what processes are “hurting” the organization. Their direct reports then translate the broad topics into doable projects. Once the projects are prioritized, process improvement teams are assigned to work on the problems.

How should I select training projects?

A training project must first be a Six Sigma project; that is, there must be an evident opportunity for improvement of a chronic problem. In addition, the project should have a fairly wide scope so that the candidate can practice as many of the important skills as possible.

How big should process improvement teams be?

Depending on the complexity of the problem and the need for cross-functional representation, 6 to 12 people typically serve on a process improvement team. The group should consist of a team leader, usually a Black Belt, one or more Green Belts to help with data analysis, and subject matter experts to provide the necessary technical skills and knowledge. In addition, each team should have a sponsor and a coach.

What is a project sponsor?

The project sponsor is a member of senior management who champions the project among the executive team, coordinates resources and resolves possible conflicts that may ensue, and assists in overcoming managerial obstacles.

What is a coach?

The coach, or Master Black Belt, advises the team on Six Sigma methods, provides advanced methods when needed, helps to facilitate optimal team dynamics, and provides supplementary training when required.

How long do process improvement projects last?

Process improvement projects typically last three to six months and rarely take longer than nine months. If the project is completed in too short a time, it is either not a true sigma project or nothing is accomplished to satisfaction. If the project takes too long a time, frustration and impatience set in and everyone grows anxious to move on. Such lengthy projects need to be divided into more easily managed subprojects.

How much time should a person spend working on the improvement team tasks?

How much time a person should spend working on improvement team tasks depends on the resources available and how much time management is willing to assign to the project. Typically, team members spend about 25% of their workday on the project the team is tackling. This time should be carefully tracked by the accounting department. Also, it is important to note that this time is allocated during working hours, not after the workday is over.