Jun 8, 2011

Understanding How CP and CPK Are Used to Ensure Quality

The purpose of this application note is to explain what Cp and Cpk are and how these statistical tools can be used to prevent shipping marginal products. Most people have at least heard of Cp or Cpk, but few people really understand the concepts behind the calculations. This is valuable information not just for Quality Managers, but also for the Engineers who design new products, as well as Purchasing Agents who have to maintain a list of qualified vendors. In fact the 1994 revision of ISO 9000 requires suppliers to evaluate their subcontractors on the basis of their ability to meet subcontract requirements (Section 4.6.2).