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Acing the quality game: Lean Six Sigma

Acing the quality game: Lean Six Sigma

In manufacturing, one measure of the efficiency and quality of a process is its sigma rating – which can refer either to yield or the percentage of defect-free products it creates. The number in front of the sigma symbol (σ) indicates where the process’s output lies on the bell curve of standard deviation. 1σ is terrible, with 69% of products coming off the production line with defects – a massive waste of resources. 2σ would see around a 31% defect rate. 3σ would be about 7%.

When you get to (six sigma), the defect rate is 0.00034%, or 3.4 defects per million. Clearly, achieving this level of production quality is far preferable to any of the lower sigma numbers, and those involved in Six Sigma quality management strive to achieve or surpass it though a set of statistical management methods. These methods can be applied to other industries, not only to manufacturing. In healthcare, for example, it is clearly desirable that error rates be minimised. Supply chain logistics and construction are another examples.

The overall Six Sigma methodology is enshrined in the mantra DMAIC: Define, Measure, Analyze, Improve and Control. Within, between and across these phases, statistical tools are applied such as regression analysis, the chi-squared test and analysis of variance. The aim is continuous improvement, with 6σ as the gold standard (some have pointed out that in some complex manufacturing processes this is not enough. For example, in silicon chip manufacturing where millions of transistors are applied to a single chip, a defect rate of 3.4 in a million would render every single chip defective and unusable).

Six Sigma and associated management techniques form part of the Quality Management industry, a nexus of consultancy and training firms who help companies apply these techniques to their processes. The Six Sigma training industry uses a martial arts analogy to delineate various levels of expertise. Training and consulting firm Vector International offers White Belt, Green Belt and Black Belt programs that build on each other in progression.

As you might imagine, White Belt is Six Sigma 101, introducing the fundamentals, like identifying the 8 forms of wastes and understanding the cost of poor quality to the organization.

Green Belt builds on White Belt and delves into the statistics involved in Six Sigma. The DMAIC methodology is used to solve a business problem within the participant’s area of operations.

Black belt is Chuck Norris stuff. An extended period of training (3 months) sees participants apply their knowledge to projects and get skilled up in the organizational change management they will need when rolling out Six Sigma in their enterprises. Specific techniques for eliminating wastes and crunching data are taught, applied and tested.

There are levels above Black Belt, but these are Bruce Lee territory. They are the kind of programs you don’t choose; instead, they choose you. But the path to Six Sigma enlightenment – and improved profitability – starts at the White Belt boot camp.