We’re all amateurs — learning as we go. Keep up the great work. DailyKaizen is honest and free of pre-tense. I love it.

Excellent addition/correction and good information for an amateur like me. Continuous improvement of the posts on this blog is most welcome!

Capability, on the other hand, is a question about whether or not the performance of a process is meeting the requirements of the customer. Capability, is typically a range (x to y) or, in some companies, is actually an arbitrary number (must serve customer within blah, blah, blah).

The Taguchi Curve teaches us that if there is a slight deviation of the mean either to the left or right of what he calls “target”, then cost jump exponentially. Imagine producing tire with a required thickness — if it’s too thick or too thin, the costs are very high in warantee claims or death.

What is missing in your picture is…capability, which can be shown as a C (which is a point estimate) or Cpk, which is a range (capability index).

All that is shown in the picture is really the facts.

Yes..almost. The key is that there were 5 of us hammering nails, and that’s why there appear to be multiple distributions on the histogram.

You could say that most of us had “control” because we have narrow standards of deviation. It looks like one person may have had good “control” and was “capable” (the customer’s tolerance relative to the sig sigma of that person was high), but overall, the process is not capable because it has a wide six sigma relative to the customer’s expectations, because of the variability of individuals on the team.

I took this and asked, “Suppose there are 5 family physicians in a medical center, and each of them practices uniformly according to what they learned in medical school, yet each of them learned a different way. Do they have good control? Yes. Is their care process as a team capable? Maybe not….”

It looks like each individual was capable, but the “process” overall was not capable, correct?