M. Performance Characteristic Not Good EnoughOverviewMany processes, particularly in manufacturing industry, are judged heavily on a performance characteristic such as strength, assay, thickness, viscosity, color, flatness, and so forth. When these characteristics are judged by the Customer to be not good enough, in effect we are creating defective entities. This is essentially the same problem as described in Section C in this chapter for defect reduction and thus will not be considered as a separate Problem Category. Examples
Measuring PerformanceUse the performance characteristic itself as the measure. These metrics tend to be continuous in nature and make excellent Ys for use in Section C in this chapter. Statistical power will be lost if they are converted to an attribute measure of defectiveness (meeting specification or not). In Lean Sigma terms, we have taken a useful performance metric and converted it into a not-so-useful conformance metric. Tool ApproachSee Section C in this chapter. Special attention should be paid in particular to the Measurement Systems Analysis because oftentimes this in itself can resolve the problem. |