D
DJN
I am trying to understand the difference between Cpk and Ppk and when to use them. I think I have it sussed, but I am not sure. I have been trawling through reams and reams of literature until my head spins. OK. So far, I think I should be using Cpk when the process is in control and the data is normally distributed, and Ppk when the process is unstable and/or the data is not normally distributed. Are my assumptions right? I am also confused about the terms 'Short term' for Cpk and 'Long Term' for Ppk. I have read on this forum that, "Cpk attempts to answer the question, does my process in the long run meet specification?. So why is Cpk short term? Any help and guidance appreciated.
David
David