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Sigma-level analysis provides a quantum leap in management's understanding and control of the quality process. The proprietary method uses level-of-defectives isograms to discover and display the sigma-level performance and probable yield of processes, using only process data, targets, and tolerances as inputs. Defectives are defined as errors, faulty parts or actions, and out-of-tolerance variables. Note that SPC is inadequate as a mechanism for quantitative analysis of in-control high-yield processes. SSIAM provides identification of rogue variables that prevent the achievement of high yields in critical processes. Typical performance goals for product and process variables range from 4-1/2 sigma (one defective per thousand) to 6 sigma (less than 4 defectives per million). A factory audit using SSIAM frequently uncovers product/process variables that meet SPC criteria, but exhibit/perform at sigma-levels of three (yield of 93.3%) or lower. Bob Horst is founder and principal consultant. He may be reached at horst@peaksigma.com, P.O. Box 681, Lancaster, PA 17608, and 717-299-7217. |