Government Electronic & Information Technology Association
Scope
Given the clear relationship between superior quality offerings (goods or services) and superior
business performance, many businesses have found it desirable to measure the progress of their
multifaceted quality improvement efforts.One technique that can be utilized as a quality
improvement monitor, as well as a driver for a quality improvement effort, is the process
capability index (Cpk). This technique, introduced in EIA-557 titled "Statistical Process Control
Systems", relates performance to specifications on selected quality-related characteristics.