Chapter 7
Six Sigma In Chapter 6, we discussed the lean concept and how it can be used to eliminate waste and create value for the customer. In this chapter, we present the concept of Six Sigma, which is aimed at reducing process variation and improving accuracy. Lean and Six Sigma (or as some call it, Lean Sigma) are often considered linked by people working on quality improvement projects. The goal of Six Sigma is to eliminate process variations, thereby achieving predictability. Dr. W. Edwards Deming, the American statistician who is one of the people credited with Japan’s revitalization, defines quality as “A predictable degree of uniformity and dependability at low cost and suited to the market.” A lack of internal consistency confounds constancy of purpose and makes it impossible to create goods and services that would consistently meet or exceed customers’ expectations. When present, variations rob an organization of the ability to deliver goods and services to customers predictably. A lack of predictability erodes the customers’ trust in an organization’s ability to deliver on its promises. Process variations are deadly and should be handled with the urgency that their impact demands. Analyzing medical death rate data over an eightyear period, Johns Hopkins’ patient safety experts (Makary and Daniel, 2016) have determined that more than 250,000 deaths per year are due to medical error in the United States. Their figure, published May 3, 2016 in The BMJ, surpasses the U.S. Centers for Disease Control and Prevention’s (CDC’s) third-leading cause of death—respiratory disease, which kills close to 150,000 people per year.
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