Sigma, s , is used by statisticians to measure variation in any process. Six Sigma in turn means a very high quality level of 3.4 or less defects or errors per million opportunities for defects or errors in products or services. The beauty of Six Sigma is that it is both an engaging management philosophy with realm of possibilities, as well as a structured tool that can help any organisation achieve world class performance.

Six Sigma emphasizes financial measures to prove the benefits. Process and quality improvements are quantified in financial terms and is also the basis used in project selection and prioritisation. Because of this strong relationship with financial performance, there is greater accountability and Top Management engagement.

Six Sigma can be viewed in different ways - as a metric, a principle, as a methodology, as well as a management system.

As a metric, Six Sigma prescribes the disciplined use of fact-based data. By consistently applying a systematic data-driven approach, Six Sigma practitioners are able to increase predictability, consistency and accuracy of processes in producing defect-free products and error-free services.

As a principle, Six Sigma's core is variation reduction. It is variation in processes that leads to defects, cost of poor quality, customer dissatisfaction as well as market loss and lost opportunities. By focusing on strengthening its processes and making them more reliable and capable, the organization will achieve superb quality levels, greater efficiencies and higher levels of profitability.

As a methodology, Six Sigma is tested and validated by General Electric, Samsung, Bank of America and many global enterprises. The five phase Define, Measure, Analyze, Improve, and Control methodology together with a comprehensive suite of statistical tools explain its success compared to the many unsubstantiated management philosophy out there.

As a management system, Six Sigma is an enterprise-wide improvement initiative that is applicable in operations, sales, design, procurement, logistics and any process in the organisation. Management must lead the Six Sigma initiative and is responsible to define a set of key performance metrics, measure their actual performance and initiate improvements to the system.

The upshot is, in challenging the entire organisation to achieve a Six Sigma level of near perfection, Six Sigma captures the imagination and has proven to inspire dramatic improvements to the bottom line.

Design for Six Sigma (DFSS) may be viewed as a cohesive framework of tools and techniques for product development that addresses a niche that is not fulfilled by Six Sigma nor typical product development models. For instance, Six Sigma focuses on the improvement of an existing process(es), while DFSS focuses on the creation of new value and allows one to achieve the desired "built-in" quality level even with variations in the manufacturing or service operations. DFSS also plugs in the shortfall of many product development models in terms of measurement and prediction with its array of tools and techniques.

Unlike Six Sigma, DFSS has various methodologies with different names, acronyms and phases. Some of the common ones include: DMADV (Define, Measure, Analyze, Design and Verify), IDOV (Identify, Design, Optimise and Validate) and DMEDI (Define, Measure, Explore, Develop and Implement). However, a closer look reveals the same agenda and design tools.

The heart of DFSS is a clear understanding of the market, with intimate knowledge of the customer quality requirements as the linchpin. This is why a design that has gone through DFSS would be well-received in the market. These inputs are then translated to critical technical characteristics through the use of specific tools and subjected to various analyses to ensure that the design will be cost-effective and reliable. Next, in order to ensure that the design is robust and reliable in the face of variations in the subsequent operations or manufacturing, predictions are made, failures are anticipated, mistake proofing is done, process capability is enhanced, and tests, reviews and validations performed to ensure that the design meets the desired sigma level.

Hence, with DFSS, one ultimately gets a product or service that is assured of market-receptiveness and is both reliable and robust.

For DFSS, data to measure the benefits can only be collected 6 to 12 months after the launch of the new product. Generally, the following benefits can be expected: