Herman, John T. (1989, ASQC) E.I. du Pont de Nemours & Co., Inc., Old Hickory, TN
As we all today, continual improvement in product quality is required for survival in many businesses. This emphasis on continual improvement has created a need for measures that verify improvements actually occur. One measure has gained wide distribution throughout the United States and Japan, and this is the so-called Capability Index, with all its modifications.
In this paper, I will define for you what is meant by the phrase 'Continual Improvement' and what the Capability and Performance Indexes are, discuss differences between the mechanical and process industry producers, and show why Capability and Performance Indexes as measures of continual improvement may be misleading for many products of the process industries; I will also propose an alternative measure thar removes the deficiencies surrounding these indexes.
Chemical and process industries