4. In-process control

The idea of control charts originated with the American W. Shewhart (1931); their use, slow at first, was first developed in the USA in 1939-1945, and in Europe ten years later. Some major French industries began using them more systematically around 1965 (e.g., the textile industry), and training centers, particularly in France's Centre d'Enseignement et de Recherche de la Statistique Appliquée (CERESTA), made a major contribution to their use from that time onwards. The driving force behind their current development, however, is the NF EN ISO 9000 quality standards; their popularization has been facilitated by Afnor/ISO statistical standards and the practical teaching of statistics in engineering schools.

Statistical control methods used to control a process are based on sampling theory, and make it possible to define when a process has probably drifted (in position...