Statistics for Six Sigma Made Easy

5.2. WHAT WE HAVE LEARNED IN CHAPTER 5

1. The fishbone diagram is used primarily in the Define, Analyze, and Improve steps of the DMAIC process.

2. Look for possible cause-and-effect relationships using a fishbone diagram. The purpose of a fishbone diagram is to have experts identify all the input variables that could be causing the problem of interest. Once we have a complete input variables list, we must attempt to identify the critical few key process input variables (KPIVs) to measure and further investigate.

3. The fishbone diagram is the preferred Six Sigma tool for identifying what should be sampled in a process and which variables need to be kept in control during the sampling process. Without the kind of cause-and-effect analysis the fishbone ...