When the U.S. forces occupied Japan at the end of World War II to set up the occupation government, they found the Japanese telephone system to be poor in quality and unreliable. General MacArthur’s people knew this would be a major problem for them and for Japan in trying to get the country on its feet again. Bell Laboratories’ people were brought in to assist the Japanese telecommunications industry, and starting in May 1946 they taught their Japanese counterparts the principles of modern quality control based on Dr. Shewhart’s work.

While the Bell Labs people were in Japan, a copy of Shewhart’s book The Economic Control of Quality of Manufactured Product was given to the Union of Japanese Scientists and Engineers (JUSE). One of its members (the organization had only 12 at the time) was so taken with Shewhart’s ideas that he stenciled by hand a copy of the book onto mimeograph masters, so that it could be reproduced and circulated. These two events were the start of the quality movement in Japan.

QUESTIONS  

1. What was Shewhart’s source for the data required for his statistical process control?

2. Shewhart describes two kinds of variation, that resulting from common causes and that resulting from special causes. Define both.