Visual Six Sigma: Making Data Analysis Lean

8.8. Utilizing Knowledge

In spite of this very promising result, Carl reminds his teammates to remain cautious. Even if they had made no process changes, history shows that a crisis is only expected about once every quarter. During the single crisis that occurred over the team's baseline period, MFI values were unusually high. So there is statistical evidence that keeping MFI within the specification limits will alleviate crisis periods. But it will be important to continue to monitor Yield to ensure that the new optimal settings and controls really do address the root cause of a crisis. As they gather additional data over a longer time span, they will have more assurance that keeping MFI and CI within their specification limits really does alleviate crises.

This is an interesting situation where, although success has been confirmed in the short term, the longer time horizon of the historical problem requires a heightened sense of vigilance during the control phase. So, although the team is ready to see its project move to the Utilize Knowledge step of the Visual Six Sigma Data Analysis Process, that step will still retain some aspect of providing confirmation that the problem has been solved.

With this in mind, Carl and his team report their results to Edward. He is very impressed by the outcome of the confirmation runs and is extremely pleased by the work that Carl and his team have done. He appreciates the logic and discipline they have imposed throughout the knowledge-building ...