In Greg Brue’s book, SixSigma for Managers, Brue puts forth a method designed to act as a road mapto assist managers become more effective and invaluable to their company. Byfirst understanding the basic principles of six-sigma referred to as DMAIC:define, measure, analyze, interpret, and control. Then, its implementation andkey tools and roles in order to enhance a company’s process and profits. From the onset, Brue wants the reader to recognizethat six-sigma is not just a management approach, but also a statistical baseof measurement, a philosophy and goal, a methodology and an image of quality.
Thatbeing said, in statistics the concept “sigma” is used to depict standarddeviation, a symbol that represents the amount of variation in a process ormeasurement. For reference, Brue details sigma levels and its correspondingdefects per million opportunities: a sigma level of 2 corresponds with 308,537defects, a sigma level of 3 corresponds with 66,807 defects, a sigma level of 4corresponds with 6,210 defects, a sigma level of 5 corresponds with 233defects, and lastly a level of 6 corresponds with 3.4 defects. This leads us toa statistical approach that measures defects in a process, known as six-sigma. Essentially,six-sigma is to be at 99,9997% as perfect as possible. If perfection wereattainable why would an organization operate at anything other than a sigmalevel of six? In fact, Brue states that most organizations in the United Statesoperate at the minimum sigma level of three and four: 99.
379%. Theseorganizations believe this to be an adequate level but in reality it representspoor performance. So, why operate at 99.379% when you can be at 99,9997%? Ifthat’s the case then why do most organizations in the United States operate at theminimum sigma level of three or four which is 99.379%? In fact, organizationsbelieve 99.379% to be an acceptable level but in reality it translates to extremelypoor performance. However, is 99.
379% enough to persuade an organization toadopt six-sigma? The answer to this is money, customer satisfaction, quality,growth, competitive advantage, and employee pride. Unlike other qualityapproaches Brue wants to assure his readers that six sigma is not a trend andcorroborates this by providing success stories of companies like Motorola, GEand AlliedSignal. These companies all reported increasing their profits bybillions since their six-sigma inception in which Brue credits to theelimination of poor quality and its cost – scrap costs, rework, plus excessivecycle times and delays. This translates into the cost of business lost due todissatisfied customers and cost of opportunities lost due to a lack of time orresources.
Using Deming’s view of quality Brue develops critical-to-quality(CTQ), which is “elements of a process that significantly affect the output ofthat process. Identifying these elements is figuring out how to makeimprovements that can dramatically reduce costs and enhance quality