Davis Balestracci Bio Six Sigma Control Charts: Simple Elegance or Legalized Torture? Once again, I’m beginning to understand Deming’s hatred of statistical ‘hacks’

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Author Archive For all the talk about the power of control charts, I can empathize when audiences taking mandated courses on quality tools are left puzzled. When I look at training materials or books, their tendency is to bog down heavily in the mechanics of construction without offering a clue about interpretation. Some seminars even teach all seven control charts! And then there is the inevitable torturous discussion of "special cause tests" (usually the famous eight Western Electric rules). People are then left even more confused. Does each test signal need to be individually investigated, i.e., treated as a special cause? Not to worry—most people usually investigate only the points outside the control limits. The focus tends to be on individual observations. But what if there is one underlying explanation generating many of these signals that has nothing to do with individual outliers, e.g., a step change? Someone once presented me with the graph shown in figure 1. (Yes, the y-scale started at 0.) It almost convinces you that there is a trend, eh? Like what you're reading? Log in or create FREE account to continue Enter your Quality Digest username OR email address. Enter your Quality Digest password. Remember me Create a FREE account Forgot My Password Quality Digest does not charge readers for its content. We believe that industry news is important for you to do your job, and Quality Digest supports businesses of all types. However, someone has to pay for this content. And that’s where advertising comes in. Most people consider ads a nuisance, but they do serve a useful function besides allowing media companies to stay afloat. They keep you aware of new products and services relevant to your industry. All ads in Quality Digest apply directly to products and services that most of our readers need. You won’t see automobile or health supplement ads.



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Quality Digest Discuss About The Author Davis Balestracci Davis Balestracci is a past chair of ASQ’s statistics division. He has synthesized W. Edwards Deming’s philosophy as Deming intended—as an approach to leadership—in the second edition of Data Sanity (Medical Group Management Association, 2015), with a foreword by Donald Berwick, M.D. Shipped free or as an ebook, Data Sanity offers a new way of thinking using a common organizational language based in process and understanding variation (data sanity), applied to everyday data and management. It also integrates Balestracci’s 20 years of studying organizational psychology into an “improvement as built in” approach as opposed to most current “quality as bolt-on” programs. Balestracci would love to wake up your conferences with his dynamic style and entertaining insights into the places where process, statistics, organizational culture, and quality meet.