In Greg Brue’s book, SixSigma for Managers, Brue puts forth a method designed to assist managersbecome more effective and invaluable to their corporations by firstunderstanding the basic principles of six-sigma referred to as DMAIC: define,measure, analyze, interpret, and control. Thereby acting as a road map formanagers these principles along with provided tools and key roles will enhance acompany’s process and profits. From the onset, Brue wants the reader tounderstand that six-sigma is not only a management approach, but that its alsoa statistical base of measurement, a philosophy and goal, a methodology and animage of quality. That being said, the term “sigma” is used in statistics to depictstandard deviation, a symbol that shows the amount of variation in a measurementset.
For reference, Brue details various 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 sigma level of 6 corresponds with 3.4 defects. This leadsus to six-sigma, a statistical approach that measures defects in a process. Essentially,to be at six-sigma is to be at 99,9997% as perfect as possible. If perfectionwere attainable why would an organization operate at anything other than asigma level of six? In fact, Brue states that most organizations in the UnitedStates operate at the minimum sigma level of three and four: 99.
379%. Theseorganizations believe it to be an acceptable level when in actuality itrepresents very poor performance. So, why operate at 99.379% when you can be at99,9997%? If that’s the case then why do most organizations in the UnitedStates operate at the minimum sigma level of three or four which is 99.379%? Infact, organizations believe 99.
379% to be an acceptable level but in reality ittranslates to extremely poor performance. But is 99.379% enough to persuadeorganizations to adopt six-sigma? The answer to this is money, customersatisfaction, quality, growth, competitive advantage, and employee pride. Unlikeother quality approaches Brue wants to assure his readers that six sigma is nota trend and corroborates this by providing success stories of companies like Motorola,GE and AlliedSignal. These companies all reported increasing their bottom lineby billions since their six-sigma inception.
Brue credits this to the cost ofpoor quality – cost of scrap, rework, and excessive cycle times and delays.This translates into the cost of business lost due to dissatisfied customersand cost of opportunities lost due to a lack of time or resources. UsingDeming’s view of quality Brue develops critical-to-quality (CTQ), which is”elements of a process that significantly affect the output of that process.Identifying these elements is figuring out how to make improvements that candramatically reduce costs and enhance quality