The modern age of Quality was ushered in by Walter Shewhart.

Shewhart developed  statistical control charts for the control of  industrial processes. His control chart techniques have been widely adopted.

Shewhart successfully brought together the disciplines of statistics, engineering, and economics and became known as the father of modern quality control.

He also developed the Shewhart Learning and Improvement cycle, combining both creative management thinking with statistical analysis.  This cycle contains four continuous steps: Plan, Do, Study and Act.  These steps (commonly referred to as the PDSA cycle), Shewhart believed, ultimately lead to total quality improvement.  The cycle draws its structure from the notion that constant evaluation of management practices -- as well as the willingness of management to adopt and disregard unsupported ideas --are keys to the evolution of a successful enterprise.