Cpk Versus Ppk

Narrated PowerPoint presentations on Capability Analysis are available here via the American Society for Quality (ASQ)

Title: C_pk Versus P_pk
Author: Keith M. Bower
Publication Source: American Society for Quality, Six Sigma Forum, April 2005

Abstract

Understanding the concept of "long-term" versus "short-term" variation is crucial to obtaining valid results from capability studies.

Notes

My goal for this paper was to address the difference between the statistics, and illustrate why the occasionally fierce debate between practitioners is moot when sampling from a stable system. My understanding of capability analysis procedures, and requirements for legitimacy in interpretation, is more fully fleshed out in the paper on Non-Normal Capability Analysis.

Download this video (free) through this link (iTunes opens):

A discussion on "What is Ppk?" is in the Video Podcast below. Click the play button on the video player screen below. For Closed Captioning, start the video, then choose the upward pointing triangle at the bottom right hand corner of the player, and choose "CC".