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Six Sigma - mind map it with Mind Pad

  • Important notice: Features and functions described on this page are for Mind Pad 2, the latest version of Mind Pad was released as a new major update (actually completely new project), so information on this page will be relevant only to Mind Pad 2, which is available for download, but is not supported.
    Download Mind Pad to support quality assurance process

Six Sigma is a highly structured program for improving business processes. It was created by Mikel Harry and Richard Schroeder at Motorola in the early 1980's. Support Six Sigma process with mind mapping and Mind Pad.

Six Sigma in action:

  1. Describe processes that you want to improve/control.
  2. Add some index to the object and define your out of tolerance range. Measure your processes and Analyze why the problem occurred. 
  3. Improve the process to stay with tolerance. Redesign the process to meet customers needs.
  4. Control the process to stay within goals. Verify if the changes have met customer needs 

Six Sigma with mind map:

  1. Describe the process to be improved with Mind Pad. More about process mapping.
  2. Add some sub-topics for index, measure, improve-redesign, control-verify actions.

Six Sigma with Mind Pad:

  1. Mind Pad allows to create custom designed objects. With Mind Pad you can create custom object for Six Sigma analysis. You can design a special object with tolerance range, measure way description. Add properties to describe analysis and redesign steps, improve and verify steps.
  2. Link Six Sigma custom designed objects to process map. 


  • A process improvement methodology created by Mikel Harry and Richard Schroeder at Motorola in the early 1980's. The approach employs a rigorous project methodology, which utilizes statistical analysis to identify root causes. As a process measure, it means 3.4 defects per million opportunities.
  • Literally, refers to the reduction of errors to six standard deviations from the mean value of a process output or task opportunities, ie about 1 error in 300,000 opportunities. In modern practice, this terminology has been applied to a quality improvement methodology for industry.
  • A rigorous and disciplined methodology that utilizes data and statistical analysis to measure and improve a company s operational performance, practices and systems. Six Sigma identifies and prevents defects in manufacturing and service-related processes. In many organizations, it simply means a measure of quality that strives for near perfection. 
  • A 'measure of goodness' involving the application of statistical methods to business processes to improve operating efficiency, reduce variation, avoid defects and reduce waste. 
  • A measurement of process quality. Sigma is the mathematical symbol for standard deviation. As an example, about 93% of all results from a normal population (ie results are equally distributed above and below the mean) fall within 3 standard deviations. The use of six sigma in a manufacturing situation means that the company uses all the total quality tools to improve a process so that the tolerances for the process is at or better than six standard deviations of the process spread. This would result in no more than 3.4 failures in 1 million units of production. 
  • Six Sigma is a highly structured program for improving business processes and represents the latest incarnation of the quality movement. The program, grounded in efforts to improve manufacturing quality during the 1980s, brings the methods and analytic tools of engineers to bear on the questions, What matters to customers?, and Where will changes to work processes most improve these points? 
  • Six Sigma is a quality management program to achieve "six sigma" levels of quality. It was pioneered by Motorola in the mid-1980s and has spread to many other manufacturing companies. GE Aircraft Engines operates at Nine Sigma levels of quality. It continues to spread to service companies as well. In 2000, Fort Wayne, Indiana became the first city to implement the program in a city government. 

Improve process - two approaches


Basic methodology to improve existing processes Define: out of tolerance range. Measure: key internal processes critical to quality. Analyze: why defects occur. Improve: the process to stay within tolerance. Control: the process to stay within goals.


Basic methodology of introducing new processes. Define: the process and where it would fail to meet customer needs. Measure: and determine if process meets customer needs. Analyze: the options to meet customer needs. Design: in changes to the process to meet customers needs. Verify: the changes have met customer needs 

Six Sigma Description

Six Sigma is a quality management program to achieve "six sigma" levels of quality. It was pioneered by Motorola in the mid-1980s and has spread to many other manufacturing companies. It continues to spread to service companies as well. In 2000, Fort Wayne, Indiana became the first city to implement the program in a city government. 

Six Sigma aims to have the total number of failures in quality, or customer satisfaction, occur beyond the sixth sigma of likelihood in a normal distribution of customers. Here sigma stands for a step of one standard deviation; designing processes with tolerances of at least six standard deviations will, on reasonable assumptions, yield fewer than 3.4 defects in one million. 

Achievement of six-sigma quality is defined by Motorola in terms of the number of Defects Per Million Opportunities (DPMO). 
That is, fewer than four in one million customers will have a legitimate issue with the company's products and service. 
Many people believed that six-sigma quality was impossible, and settled for three to four sigmas. However market leaders have measurably reached six sigmas in numerous processes. 

More about six sigma

Anyone looking at a table of probabilities for the normal (Gaussian) distribution will wonder what six-sigma has to do with 3.4 defects per million thingies. Only one billionth of the normal curve lies beyond six standard deviations, or two billionths if you count both too-high and too-low values. Conversely, a mere three sigma corresponds to just 2.6 problems in a thousand, which would seem a good result in many businesses.

Mind Pad Newsletter - mind maps problems discussion, Mind Pad updatesThe answer has to do with practical considerations for manufacturing processes. (The following discussion is based loosely on the treatment by Robert V. Binder in a discussion of whether six-sigma practices can apply to software .) Suppose that the tolerance for some manufacturing step (perhaps the placement of a hole into which a pin must fit) is 300 micrometres, and the standard deviation for the process of drilling the hole is 100 micrometres. Then only about 1 part in 400 will be out of spec. But in a manufacturing process, the average value of a measurement is likely to drift over time, and the drift can be 1.5 standard deviations in either direction. At any time, 6.6% of the output will be off by 1.5 sigma in each direction. Thus, when the process has drifted by 150 micrometres, 6.6% of the product will be off by 150 + 150 or 300 micrometres, and therefore out of spec. This is a high defect rate.

If you set the tolerance to six sigma, then a drift of 1.5 sigma in the manufacturing process will still produce a defect only for parts that are more than 4.5 sigma away from the average in the same direction. By the mathematics of the normal curve, this is 3.4 defects per million.

There is another reason for six sigma: a manufactured item probably has more than one part, and some of the parts will have to fit together, which means that the total error in two or more parts must be within tolerance. If each step is done to three-sigma precision, an item with 100 parts will hardly ever be defect-free. With six-sigma, even an object with 10,000 parts can be made defect-free 96% of the time.

News and featured articles about knowledge representation. Learn about mind maps, concept maps, process maps and other visualization techniques. Clearly, many things on which people rely (services, software products, etc.) are not manufactured by machine tools to particular measurements. In these cases, "six sigma" has nothing to do with statistical distributions, but refers to a goal of very few defects per million, by analogy to a manufacturing process. The usefulness of the analogy is controversial among those concerned with quality in non-manufacturing processes. 


More about Quality Management

Learn more about methods of quality management and how to use mind mapping and Mind Pad to support them. Learn about Total Quality Management method, SWOT analysis, Six Sigma quality program.

  • Total Quality Management (TQM). Quality assurance through statistical methods is a key component in a manufacturing organization. Learn how to mind map TQM. 

  • SWOT analysis is a strategic planning tool used to evaluate the Strengths, Weaknesses, Opportunities, and Threats. Use Mind Pad to support your SWOT analysis.

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