Continuing our series on quality control systems, this blog post will focus on the system known as the Deming cycle.  Originally developed by Dr. W. Edwards Deming in the mid-1900’s, the Deming cycle is also known as the Shewhart cycle, the control circle or cycle, or plan-do-study-act (PDSA).

The Deming cycle is a four-step management method used in business for the quality control and continuous improvement of processes and products.  The system is used as the basis criteria for many quality control certificates, including AS9100.

Dr. W. Edwards Deming (1900-1993) was born an American but spent a large part of his career in Japan.  He is recognized as a major contributor to Japan’s later reputation for high-quality products.  His impact on Japanese business and industry is considered the greatest of any non-Japanese.

Despite his theories’ high value in Japan, Deming and his Deming cycle were only beginning to receive recognition in the U.S. at the time of his death.  He was awarded the National Medal of Technology in 1987 and the National Academy of Sciences’ Distinguished Career in Science award in 1987.

Deming was trained initially as a statistician and began his career developing improved methods for national census taking.  He went on to build a profitable consulting business and was very in demand at the end of his long life.  One of his most well-known triumphs is turning sales around at the Ford Motor Company, helping the company raise profits to ultimately become the highest-performing automotive company in the U.S.

Deming’s philosophy focuses on transforming the management culture of a company to focus on continual quality improvement.  The basis for the Deming cycle was developed by Deming’s mentor, the statistician Walter A. Shewhart.  In fact, Deming called his cycle the “Shewhart cycle” during his lifetime.  Shewhart first developed a three-step scientific process of specification, production, and inspection.  This cycle is very closely based off the scientific method of hypothesize-test-analyze.  This method allows for continual improvement of a process based on experience and results.

The Deming Cycle takes this method further with one extra step.  Deming stressed the importance of constant interaction among the four steps of design, production, sales and research.  He emphasized that these steps should be rotated constantly, with quality of product and service as the aim.  The Deming cycle includes:

1. Design

Establish the objectives and processes necessary to deliver results in accordance with customer requirements and the organization’s policies.

2. Production

Implement the processes.

3. Sales

Monitor and measure processes and product against policies, objectives and requirements for the product and report the results.

4. Research

Take actions to continually improve process performance.

Japanese businessmen created the well-known PDCA from the Deming cycle, using Plan-Do-Check-Act in place of Design-Production-Sales-Research.The PDCA cycle emphasizes the prevention of error recurrence by establishing standards and the on-going modification of those standards.  Deming considered the PDCA cycle to be more applicable to quality control and the Deming cycle, or as he later termed it the plan-do-study-act (PDSA) cycle, to be more suited to enhancing management systems. 

Today both the Deming cycle and the PDCA cycle are used to improve companies’ production levels and quality.  The cycle aims to take management’s focus off of the bottom line to focus more on quality improvement.

Do you use the Deming cycle or PDCA in your company?  How has it worked for you?  Let us know in the comments below!



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