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Cpk: Indispensable index or misleading measure?

Cpk is a critical index often used to assess quality and maintain customer-supplier relationships. However, if misemployed, Cpk can cause more harm than good. If you provide capability indices to your customers or you require them from suppliers, join this webinar to learn the five steps necessary for legitimate capability analysis.

Date: June 12, 2019
Time: 3 PM EDT (12 PM PDT / 9:00 PM CEST)
Duration: 1 hour
Presented by:


The primary statistics resulting from capability analysis are the capability index (Cpk) and the performance index (Ppk). Capability analysis can add value in the supply chain, if you proceed with caution. Mark Twain said "Facts are stubborn things, but statistics are pliable." Both when consuming and when producing a Cpk result, be aware that Cpk is easily manipulated. Whether you are the producer or the customer, if you are using capability analysis for decision making in your organization, you must fully understand its use. Computing Cpk is not difficult. Understanding whether or not the value is a reasonable representation of the underlying process, however, is critical to using capability analysis effectively. Join us for this important, 60-minute webinar where you will learn the five steps necessary for legitimate capability analysis. Capability analysis is a set of calculations used to assess whether a system can meet a set of requirements. Customers, engineers or managers usually set the requirements, which can be specifications, goals, aims or standards. The primary reason for doing a capability analysis is to answer the question: Can we meet customer requirements? Capability analysis involves two entities: 1) the producer and 2) the consumer. The consumer sets the requirements and the producer must be able to meet them. Capability analysis can be used as structured communication that flows between producers and consumers. This communication happens up and down the supply chain and is useful in different contexts. For example, it can be useful when a manufacturer is considering the purchase of a new machine. It can be useful when a producer is working through the Production Part Approval Process (PPAP), or during contract and pricing negotiations between a producer and a potential customer.

Key Takeaways

  • Learn the primary way Cpk can be a misleading statistic
  • Understand how to avoid being misled or misleading others
  • Discover tips for how to improve your Cpk
  • Gain a better understanding of process stability and process capability
  • Learn effective ways to present capability analysis


Steve Daum, Director of Software Engineering, PQ Systems

Steve Daum is director of software engineering for PQ Systems. He has more than 30 years of experience with statistical process control, control charts, and control charting software. Steve has published papers in a variety of professional journals and has led multiple seminars and presented on statistical process control and issues related to quality to a variety of audiences in the U.S., England and South Africa.

Matt Savage, VP of Product Development, PQ Systems

Matt Savage is vice president of product development for PQ Systems. He is an experienced consultant to organizations that want to utilize the power of data analysis to improve processes and enhance profitability. He has worked extensively with technical advisory teams and has provided on-site consulting and training in statistical process control for a variety of organizations representing manufacturing, health care and service organizations in the U.S. and abroad.