Deming circle

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The four phases of the PDCA circle related to the ISO 50001 standard (energy management systems)

Deming circle or Deming wheel , Shewhart Cycle , PDCA cycle describes an iterative three- or four-phase process for learning and improvement by the US physicist Walter Andrew Shewhart . PDCA stands for the English plan - do - check - act , which in German is also translated as 'plan - do - check - implement' or 'plan - implement - check - act'. The origins of the process lie in quality assurance .

Concept and history

In the 1930s, Shewhart was working on quality improvement at a Western Electric plant . Developed from the findings of W. Edwards Deming a course "with other Statistical Process Control " ( Statistical Process Control ), the during the war years visited about 35,000 engineers in the United States. In 1939, Shewhart published a book entitled “Statistical Method from the View of Quality Control ”, which Deming revised. There you can find the first version of the "Shewhart cycle":

Specification → Production → Inspection

The underlying idea was the systemic consideration of the production processes. However, Shewhart did not like the sequential representation.

“These three steps must go in a circle instead of in a straight line, as shown… It may be helpful to think of the three steps in the mass production process as steps in the scientific method. In this sense, specification, production and inspection correspond respectively to making a hypothesis, carrying out an experiment, and testing the hypothesis. The three steps constitute a dynamic scientific process of acquiring knowledge ”

“These three steps have to be in a circle, instead of in a straight line as shown… It can be helpful to think of the three steps as a scientific method in mass processes. In this sense, specification, production and testing correspond to 'creating a hypothesis', 'performing an experiment' and 'checking the hypothesis'. These three steps represent a dynamic, scientific process of knowledge acquisition. "

- Walter Andrew Shewhart

The Shewhart cycle was thus represented as a circle to illustrate the continued application of the principle.

The term Deming circle is derived from W. Edwards Deming (1900-1993). The American physicist and statistician had studied with Shewhart, took up and disseminated his ideas and thus had a decisive influence on quality management . As a result, the cycle was awarded to him and in many countries referred to as the Deming circle or something similar. Deming himself spoke consistently of the Shewhart cycle , as he attributed the idea to Shewhart. Alternatively, from the abbreviation of the steps of the cycle, the terms PDCA cycle or in German translation PTCA cycle (for plan / do = carry out; check = check; - action = act / act).

When the American occupation forces in Japan under General Douglas MacArthur had quality problems with the locally produced radios, Deming was invited by Ishikawa Ichirō , the father of Ishikawa Kaoru , to give a lecture at the suggestion of some quality assurance experts. On July 13, 1950, Deming gave a presentation to executives in 21 industries in Japan. Ishikawa's group would have a decisive influence on quality development in Japan for the following decades, while statistical methods in the USA became meaningless after the war.

Four steps

Phases of the PDCA cycle

Deming added a further step to the Shewharts three-step process to depict the evolutionary quality development. This gave the process the four-stage display format that is common today. A Shewhart cycle became a step in a system's continuous improvement process . In accordance with the human relations approach preferred by Deming, he moved the work system ( Gemba ) into focus: “ Go to the place where it all happened ” and, above all, places the employees on site with their precise knowledge of the situation at the workplace at the center of the planning .

The PDCA cycle consists of four elements:

plan
The respective process must be planned before it is actually implemented: the plan includes the identification of potential for improvement (usually by the employee or team leader on site), the analysis of the current status and the development of a new concept (with the employee being closely involved).
do
Contrary to popular belief, Do not mean the introduction and implementation on a broad front, but the trying out or testing and practical optimization of the concept with quickly realizable, simple means (e.g. provisional devices) at a single workstation [again with the employee being closely involved ( Gemba )].
Check
The small-scale process flow and its results are carefully checked and, if successful, generally approved for implementation on a broad front .
Act
In the Act phase , the new general specification is introduced across the board, laid down and regularly checked for compliance ( audits ). This is actually a "big action", which in individual cases involves extensive organizational activities (e.g. changes to work plans, NC programs, master data, the implementation of training courses, adaptation of structural and process organization) as well as considerable investments (to all comparable workplaces, in all plants). Improving this standard again begins with the Plan phase .

application

Continuous quality improvement through standardization

The PDCA cycle describes the phases in the continuous improvement process (CIP). CIP is the basis of all quality management systems. Thus, in the company continuous improvement of processes and procedures followed with the aim of efficiency , customer and employee satisfaction to improve the company.

It is a standard procedure in industrial companies and in the service sector. CIP and PDCA cycle are fundamental components of the standard families DIN EN ISO 9000 , ISO 14000 , ISO / IEC 20000 and ISO / IEC 27001 Information technology - Security techniques - Information security management systems requirements specification and in BSI Standard 100-1: Management systems for Information security (ISMS) .

After each PDCA cycle, the measures are to be standardized by means of an SDCA cycle. After each introduction of a specified standards ( S tandardize), this standard is practiced ( D o), the process for accuracy and functionality checks ( C tail) and changed if necessary ( A ction). This action is then usually the planning of another PDCA cycle.

See also

  • DMAIC , a Six Sigma improvement process

Web links

Individual evidence

  1. ↑ a b c d e Peter R. Scholtes (1998) The Leader's Handbook - Making Things Happen, Getting Things Done ; McGraw Hill; doi : 10.1036 / 0071386882 .
  2. ^ R. Moen, C. Norman: Evolution of the PDCA Cycle.Retrieved May 10, 2016.
  3. ^ WE Deming; Out of the crisis ; Massachusetts Institute of Technology, Cambridge 1982, ISBN 0-911379-01-0 , p. 88.
  4. ^ WA Shewhart; Statistical Method from the Viewpoint of Quality Control ; Dover Publ., New York 1986, ISBN 0-486-65232-7 , p. 45.
  5. ↑ G. Taguchi, S. Chowdhury, Y. Wu; Taguchi's Quality Engineering Handbook ; Wiley, Hoboken (NJ) 2004, ISBN 0-471-41334-8 , p. 1426.
  6. ↑ a b M. Imai; Kaizen - The key to Japanese success in competition ; 6th edition. Wirtschaftsverlag Langen Müller Herbig, Munich 1992, ISBN 3-7844-7287-7 , p. 86ff.
  7. ↑ Schirrmann, Ulrich: Der Deming-Kreis Retrieved on May 11, 2016.