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Project management systems - Six sigma – part 1

Six sigma – part 1


This provides a brief over view of the Six Sigma process.

Six Sigma is a registered service mark and trademark of Motorola, Inc.
Six Sigma is designed to systematically eliminate defects. It was originally developed by Motorola.

Motorola has reported billions of dollars in savings.
Many other companies have adopted the methodology.

The details of the methodology were originally formulated by Bill Smith at Motorola.
Whilst Bill Smith is attributed with the development of Six Sigma it builds on techniques that had been around since the 1920’s.
These would have included people like Deming, Juran, Ishikawa and Taguchi.
Six Sigma brings together a few tools that are better than the sum of the parts.

Six Sigma was influenced by six preceding decades of quality improvement methodologies such as Quality Control, TQM, and Zero Defects.
The definition of a defect is nonconformity of a product or service to its specifications.

It asserts the following:

  • Business success requires continuous efforts to reduce variation in process outputs
  • Manufacturing and business processes can be measured, analyzed, improved and controlled
  • Success requires the commitment of top-level management and the remainder of the organization to achieving sustained quality improvement

A Six Sigma process is highly capable of producing output within specification.
Processes that operate with six sigma quality produce at defect levels below 3.4 defects per million opportunities (DPMO).
That is a defect level of 0.00034% or a pass rate of 99.99966%.
The goal of Six Sigma is to improve all processes to that level of quality or better.


The Six Sigma system has also been used in conjunction with the TRIZ methodology for problem solving.
TRIZ stands for:Teoriya Resheniya Izobretatelskikh Zadatch.
It was developed by a Soviet engineer and researcher Genrich Saulovich Altshuller.
TRIZ, in contrast to techniques such as brainstorming (which is based on random idea generation), aims to create an algorithmic approach to the invention of new systems, and the refinement of old systems


Under Six Sigma there are two key methodologies.
These are DMAIC and DMADV.
They were both formulated at General Electric.

DMAIC is used to improve an existing business process, and DMADV is used to create new product or process designs for predictable, defect-free performance.


This is a stepwise procedure.
The basic methodology consists of five steps:

  • Define

The process improvement goals that are consistent with customer demands and enterprise strategy.

  • Measure

The current process and collect relevant data for future comparison.

  • Analyze

To verify relationship and causality of factors.
Determine what the relationship is, and attempt to ensure that all factors have been considered.

  • Improve

Or optimize the process based upon the analysis using techniques like Design of Experiments.

  • Control

To ensure that any variances are corrected before they result in defects.
Set up pilot runs to establish process capability, transition to production and thereafter continuously measure the process and institute control mechanisms.

Note that these systems have similarities to Factorial Experiment Design.


This is a stepwise procedure.
The basic methodology consists of five steps:

  • Define

The goals of the design activity that are consistent with customer demands and enterprise strategy.

  • Measure

And identify CTQs (critical to qualities), product capabilities, production process capability, and risk assessments.

  • Analyze

To develop and design alternatives, create high-level design and evaluate design capability to select the best design.

  • Design

Details, optimize the design, and plan for design verification.
This phase may require simulations.

  • Verify

The design, set up pilot runs, implement production process and handover to process owners.

Some people have used DMAICR (Realize).
Some consider that focusing on the financial gains within Six Sigma is not really necessary as these would be achieved as the by product of a good process improvement.

Statistics and robustness

The Six Sigma methodology is a data-driven, systematic approach to problem solving, with a focus on customer impact.
Statistical tools and analysis are often useful in the process but do not need to be very advanced.
A reasonable Six Sigma project can begin with only less sophisticated statistical tools.

Many practitioners will have differing levels of understanding of the statistics involved which has brought criticism from professional statisticians.
Six Sigma is a problem-solving approach that has been used in many areas, for example, business, engineering, and production processes.

More information can be found in the online encyclopaedia Wikipedia.

Under PRINCE2® 2009 [see ‘The Complete Project Management plus PRINCE2’] planning is covered by the Plans theme.
The purpose of the Plans theme is to facilitate communication and control by defining the means of delivering the products (the where and how, by whom, and estimating the when and how much).
[see Plans - Purpose]

PRINCE2® is a Registered Trade Mark of the Office of Government Commerce in the United Kingdom and other countries.