Craig Gygi

Article / Updated 09-16-2022

You don’t have to wait until your multi-vari data are collected to start creating the multi-vari chart for Six Sigma. Instead, you can build the chart, incrementally, adding more to it as you collect more data. Multi-vari charts can be drawn by hand; in fact, the process operators themselves can create them, providing those folks with a critical opportunity to invest themselves in the discovery of the root cause and the development of the solution. A multi-vari chart looks pretty much like any other two-axis plot, with time moving from left to right on the horizontal axis and the measured process output metric plotted against the vertical axis. The multiple measurements of each unit are plotted together. Consecutive unit groupings move from left to right over time. A break in the horizontal progression of the chart indicates a temporal break in the process sampling. The multiple measurements taken on each unit are plotted as circles. A slightly modified circle designates the first, second, and third within-unit measurements. A solid line connects the multiple measurements within each unit and graphically indicates the magnitude of variation originating within each unit — the variation contribution from positional factors. An average point is plotted for each unit grouping. These unit averages are drawn as squares. If the multi-vari chart is drawn by hand, this average can be estimated. The average isn’t the center point between the maximum and minimum unit measurements; instead, think of it as the “balance point” between all the unit measurements. A long-dashed line is drawn connecting the averages of consecutive unit groupings measured. The up-and-down variation of this connecting line indicates the magnitude of variation between units, or the contribution of cyclical variation factors. A mark is plotted to show the overall average of the set of consecutive units measured. A short-dashed connecting line is drawn between the overall average points. The up-and-down variation of this connecting line indicates the magnitude of the variation between long breaks in time, or the contribution of temporal variation factors. Vertical lines are drawn along the horizontal axis to indicate the end of one temporal set of measurements and the beginning of the next. Each vertical divider embodies a relatively long duration of unmeasured process execution time. The sampling pattern repeats itself for three temporal occurrences. A typical multi-vari chart would continue for more temporal occurrences, always until enough process data are captured to match the historical levels of variation known to exist in the process. Each temporal occurrence contains the measurements of three consecutive units. Each cycle should contain at least three consecutive units, but up to five or six may be necessary. Each unit consists of three measurements of the same process characteristic. As with the temporal occurrences, having up to five or six measurements is sometimes useful. Interpreting a multi-vari chart To determine which category of input variable drives the performance of your process output, all you have to do is graphically decide which of the three types of variation — positional, cyclical, or temporal — displays the greatest magnitude of variation in your multi-vari chart. You can compare the variation types by homing in on each one separately. The vertical range of the positional variation — indicated by the height of the gray boxes— graphically depicts the magnitude of the process variation stemming from positional input factors. The vertical range between the unit averages — indicated by the height of the gray boxes — graphically depicts the magnitude of variation coming from cyclical factors. The vertical range between the temporal averages — shown again by the height of the gray box — graphically highlights the magnitude of the variation coming from temporal factors. Temporal factors are those that only change their input value across larger gaps of time but not within single units and not between consecutive units. You can see that the vertical magnitude of the cyclical variation exceeds that for the positional or temporal categories. That result is the voice of the process telling you that the real root cause of your process performance is associated with some factor whose input value changes between production or creation of consecutive units. The multi-vari chart proves that all other factors that change input value within single units or change input value over longer times don’t exert a significant influence on the performance of the process.

Cheat Sheet / Updated 02-14-2022

To apply Six Sigma to your business and produce the best results, you need to understand what Six Sigma is, the principles of Six Sigma, and the DMAIC problem-solving method. The correct tools and use of the Six Sigma scale and methods will keep your data dependable and reusable.

Article / Updated 03-07-2017

In Six Sigma, you make progress the old-fashioned way — one project at a time. In essence, projects are the unit of change; they define the collective effort by which most Six Sigma progress is accomplished. Projects represent — and in fact are — the level of granularity expressed to manage Six Sigma change, from a single process improvement to a large-scale business improvement effort. Scope the perfect project A Six Sigma project starts as a practical problem that adversely impacts the business and ends as a practical solution that improves business performance. The focus of a project is to solve a problem that is hurting key performance elements, such as the following: Organizational viability Employee or customer satisfaction Costs Process capability Output capacity Cycle time Revenue potential Begin your project by stating performance problems in quantifiable terms that define expectations related to desired levels of performance and timing. As you define your Six Sigma project, pay attention to issues that warrant a Six Sigma level of effort. Consider problems that Have a financial impact to EBIT (Earnings Before Income Tax) or NPBIT (Net Profit Before Income Tax) or have a significant strategic value Produce results that significantly exceed the amount of effort required to obtain the improvement Aren’t easily or quickly solvable with traditional methods Improve performance of a specified metric or Key Performance Indicator (KPI) by greater than 70 percent over existing performance levels Transform the problem After you’ve framed a particular problem to become a potential Six Sigma project, the problem goes through a critical metamorphosis — it transforms from a practical business problem into a statistical problem. This way, you can identify a statistical solution, which you’ll later transform back into a practical solution. In defining the project, you therefore state your problem in statistical language to ensure that you use data, and only data, to solve it. Using only data forces you to abandon gut feelings, intuition, and best guesses as ways to address your problems. You can’t solve real problems just by throwing time and money at them. You need practical solutions. Six Sigma projects provide practical solutions that aren’t complex, aren’t too difficult to implement, and don’t require extensive resources to affect the improvement. Know your goals and needs To obtain the maximum benefit from your Six Sigma projects, you must be aware of the strategic needs, goals, and objectives of the business. You should keep those key goals and objectives in mind when you decide which problems you need to solve as part of your Six Sigma projects. You begin by finding areas of the business that need improvement to meet business goals (Recognize). This approach leads you to determine the specific problems you need to solve to improve performance. Then you determine a statistical solution to your problem, implement the solution, and obtain the subsequent benefits. Where to begin? Start by assessing the higher level needs of your organization, using any knowledge obtained from the voice of the customer (VOC) and the voice of the business (VOB). The VOC is all the needs and expectations your customers have for your products and services. The VOB represents all the needs and expectations of the business. The basic idea is to assess both the VOC and VOB to identify gaps — areas where the expectations of the business and expectations of the customer are misaligned. To help zero in on problem areas, look for themes, such as the following: Accounts receivable and invoicing issues Capacity constraints Customer complaints Cycle time or responsiveness Excessive inventory levels Ineffective or defective services Product returns or warranty costs Yield and subsequent rework or scrap Determine project responsibilities In addition to transforming the problem from the practical domain to the statistical domain, Six Sigma projects also transform the ownership structure. Problems that begin in functional areas transform from line managers through Belts and finally on to process owner. Project responsibilities, accountabilities, and deliverables are divided between managers and the various Belts who perform problem-solving activities. Managers, including the process owner, are responsible for determining priorities and focus, while non-management personnel are responsible for implementing the solution and realizing the benefits. These project lifecycle relationships prevent Six Sigma deliverables from falling into the cracks. Six Sigma is a team effort. Even in the Define phase, where managers are responsible for project identification and launch, the Belts assist. Generally speaking, Belts have only 20 percent of the responsibility for defining and managing improvement, while the managers have 80 percent. Later, during implementation — the MAIC portion of the breakthrough strategy — these percentages are reversed.

Step by Step / Updated 03-27-2016

A cause-and-effect matrix — sometimes called a C&E matrix for short — helps you discover which factors affect the outcomes of your Six Sigma initiative. It provides a way of mapping out how value is transmitted from the input factors of your system (the Xs) to the process or product outputs (the Ys). With these relationships visible and quantified, you can readily discover the most-influential factors contributing to value.

Article / Updated 03-26-2016

Having the right tools and knowing how to apply them to your Six Sigma projects will help you produce accurate, acceptable, and reusable outcomes. Here’s an overview of the Six Sigma landscape:

Article / Updated 03-26-2016

The Six Sigma scale shows how well a vital feature performs compared to its requirements. The higher the sigma score, the more efficient the feature is. This table shows the universal Six Sigma scale: Sigma Level (Z) Defects per Million Opportunities (DPMO) Percent Defects (%) Percent Success (Yield %) Capability (CP) 1 691,462 69 31 0.33 2 308,538 31 69 0.67 3 66,807 6.7 93.3 1.00 4 6,210 0.62 99.38 1.33 5 233 0.023 99.977 1.67 6 3.4 0.00034 99.99966 2.00

Article / Updated 03-26-2016

Generally, Six Sigma is a problem-solving methodology that helps enhance business and organizational operations. It can also be defined in a number of other ways: A quality level of 3.4 defects per million opportunities A rate of improvement of 70 percent or better A data-driven, problem-solving methodology of Define-Measure-Analyze-Improve-Control An initiative taken on by organizations to create bottom-line breakthrough change

Article / Updated 03-26-2016

The DMAIC (Define-Measure-Analyze-Improve-Control) project method is a formalized problem-solving process of Six Sigma. It’s made-up of five steps to apply to any procedure of a business to improve effectiveness. Define: Set the context and objectives for your improvement project. Measure: Determine the baseline performance and capability of the process or system you’re improving. Analyze: Use data and tools to understand the cause-and-effect relationships in your process or system. Improve: Develop the modifications that lead to a validated improvement in your process or system. Control: Establish plans and procedures to ensure that your improvements are sustained.

Article / Updated 03-26-2016

Six Sigma is based on a handful of basic principles, and these principles create the entire Six Sigma arrangement. Here are Six Sigma’s fundamental principles: Y=f(X) + ε: All outcomes and results (theY) are determined by inputs (theXs) with some degree of uncertainty (å). To change or improve results (the Y), you have to focus on the inputs (theXs), modify them, and control them. Variation is everywhere, and it degrades consistent, good performance. Your job is to find it and minimize it! Valid measurements and data are required foundations for consistent, breakthrough improvement. Only a critical few inputs have significant effect on the output. Concentrate on the critical few. Every decision and conclusion has risk (ε), which must be weighed against the context of the decision.

Article / Updated 03-26-2016

Six Sigma initiatives always have a long list of things to do to achieve a successful project. However, there are a few things you shouldn’t do to help get you to that finish line. Keep the following tips in mind while planning for your own Six Sigma. Don’t deploy Six Sigma without a leader Some organizations deploy Six Sigma without a designated, empowered deployment leader. Sure, these companies train Belts, assign projects, provide tools, and track results. They believe breakthrough change will occur by the sum of the individual, independent efforts. But a Six Sigma deployment without a leader is like a ship without a captain: Individual crew members may know what to do in their own areas, but the project has no direction or overall progress. Make sure you have a leader on board. Don’t take too big a bite Almost invariably, the failure of any Six Sigma project can be traced to a scope that was too broad. Trying to minimize variation in an entire product, for example, is so defocused that little improvement can happen on any part of the product. Concentrating on minimizing the variation in a single critical characteristic of a product, however, allows you to dig deep enough to discover the real source of improvement. Always err on the side of scoping your projects too small. Improvement is continuous; you can always come back later and do more. Don’t think, “but we’re different” Considering yourself or your organization to be unique — so unique that what’s worked for others can’t possibly work for you — is natural. It’s also one of the most common myths people have about Six Sigma. Six Sigma is a general methodology. It has proven itself in every arena where it’s been applied — manufacturing, operations, logistics, design, supply chains, services, transactions, processing, legal, human resources, software, sales, marketing, management, healthcare, the public sector, defense contracting — the list goes on and on! Don’t fall into the trap of thinking you’re the lone exception to the rule. Don’t overtrain Not every officer of the peace needs to be trained as an elite Special Forces commando. Likewise, not everyone doing Six Sigma needs to know the details of every advanced statistical tool and method. The amount of information in Six Sigma courses has ratcheted up as consultants and trainers have competed against each other in their marketing efforts. But the fact that you can learn it doesn’t mean you need to. Only a handful of Six Sigma tools are actually used regularly. The majority of available tools are really brought out only occasionally for rare Sunday drives. Don’t get fooled into thinking that more and more knowledge is always better. And don’t think you have to use every tool on every project. Expediency in learning and in application is the key! The best system gets the right knowledge to the right person at the right time.