Shewhart, Walter A.

Walter Andrew Shewhart (March 18, 1891 – March 11, 1967) was an engineer, statistician, and physicist. He did a great deal of work in industrial quality with an emphasis on statistical process control.

He is perhaps best known for his impact on the PDCA cycle. Deming reportedly adopted it from the earlier works of Shewhart. In Out of the Crisis, Deming refers to the Shewhart Cycle as, essentially, “Plan-Do-Observe-Study”. He adds in a Step 5 and 6, which are steps 1 and 2 again, but with the addition of knowledge from the observation and study.