Quality Assurance and Regulatory Compliance
At the start of this century, mass production and the evolution of technology quickly rendered unit inspection costly, ineffective, or inapplicable. This period was marked by the birth of statistical sampling for inspection and acceptance of the product at receiving and shipping. This inspection method,
based on attributes that permit classification of lots as good or bad, did not preclude the delivery of a certain percentage of defective products to the buyer. In 1924, at Bell Laboratories in the United States, Walter Shewhart invented the control chart as a tool for measuring process variations. In general, these statistical control methods were limited to process control and to product inspection, and served to detect non-quality.