The goal of this chapter is to present you with a general feeling for what Six Sigma is about: its focus, structure, and emphasis on data. Like ISO 9001:2000 and CMMI, Six Sigma is an in-depth process improvement program. The intention of this book is to give you a summary of each of these three leading standards so that you can begin to assess which one might be right for you, or—better yet—what parts of each might help you reach your quality goals. And that brings us to the A in DMAIC.
The A in DMAIC is for analysis, analysis of the data you have collected. This is a big subject, and it is not one that this chapter can explore to the depth that might be warranted. But the central idea here—and the central activity—is to analyze the data you've collected in order to determine the root causes of defects or poor performance, and then to establish an empirical basis for improving the process.
The key is to identify root causes of process variation, or instability, not just the symptoms. The symptoms are almost always pretty easy to spot, and they often appear to be easy to fix. A jammed printer is a good example. The paper is all crumpled up around the roller. So we take out the sheet, and we're ready to go again. We fixed the symptom, but chances are, the problem is still there: a dirty roller, a misaligned sheet feeder.
With Six Sigma, the story is always in the data. That's the story of how your systems are really performing. And with Six Sigma, the solution is always in the ...