William Edwards Deming (October 14, 1900 – December 20, 1993) was an American engineer who improved how companies manage making products. He was a statistician, professor, author, lecturer, and consultant. He is perhaps best known for his work in Japan. Starting in 1950, he taught top Japanese business managers how to improve design, product quality, testing and sales. He taught the importance of using Statistical Process Control (SPC), to manage quality by measuring, or counting, many steps of complex manufacturing and services, in order to reduce the variation in results. This should reduce defects and errors. Deming described periodic monitoring, by repeating the steps of Plan-Do-Check-Act, known as the Deming Cycle.