Dr. Walter a shewhart 1891 to 1967. He has a BS and Ms. From the University of Illinois, and a PhD in physics from the University of California. Dr. shewhart worked for the Western Electric Company, a manufacturer of telephone hardware for Bell Telephone from 1918 until 1924. Bell telephones engineers had a need to reduce the frequency of failures and repairs in 1924 shewhart framed the problem in terms of assignable cause and chance cause variation and introduced the control chart as a tool for distinguishing between the two. Bringing a production process into a state of statistical control, where the only variation is chance, cause is necessary to manage process economically. shewhart is also attributed to creating the famous PDCA plan do check act cycle, also known as the Shu heart cycle.