The analysis and evaluation of a quality system using the Six Sigma benchmark: evidence for the robustness of Six Sigma processes

This paper shows how Six Sigma methods can be used to analyse the quality system of a company based on a case study. It broadens Six Sigma analysis by first comparing the qualitative characteristics of a company's quality system to benchmark Six Sigma practices. Second, it computes the company's Six Sigma metrics and compares these with the Six Sigma benchmark. It investigates how well the company's quality system performs when subjected to process drift and tightened customer requirements compared with the Six Sigma benchmark. The analysis provides richer sigma metrics than those found in published Six Sigma tables. The quantitative results provide evidence that Six Sigma processes are robust. They show that divergence of the qualitative characteristics of a company's quality system from Six Sigma practices mirrors the deviation of the performance of its process quality from quantitative Six Sigma metrics.