Understanding the PDCA Method or Deming Wheel

The PDCA or Deming wheel method, also known as the Deming cycle. It is a four-stage iterative model used for the control and continuous improvement of processes and products. This system is particularly popular in the field of quality management.

What is the PDCA method?

The PDCA method is a four-phase iterative tool used for continuous quality management and process improvement. The stages are :

1.Planning (Plan)

The first step in the PDCA cycle is to plan. This includes identifying a problem or an opportunity for improvement. Defining objectives, and planning the actions needed to achieve these objectives. It is crucial at this stage to collect relevant data for accurate analysis. This will lay a solid foundation for the following stages.

2.Implementation (Do)

After the planning stage comes the implementation stage. This ‘Do’ phase involves putting the plan into practice in a controlled way. Often starting on a small scale to test the effectiveness of the proposed solutions. This stage enables practical problems to be identified. Problems that may not have been foreseen during the planning phase.

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The third phase is verification. In this phase, the data collected during the implementation phase is analysed. The aim here is to check whether the results obtained correspond to the objectives set in the planning phase. This stage is crucial for understanding the effectiveness of the actions undertaken. And to identify any necessary adjustments.

4.Action (Act)

The final stage in the PDCA cycle is Action. Based on the results obtained and analysed in the previous stage. This phase consists of implementing improvements. If the results are satisfactory. The changes can be standardised and implemented on a larger scale. If the results are not satisfactory, a new iteration begins. Using the lessons learned to improve the plan.

Why use the PDCA or Deming Wheel?

The PDCA or Deming Wheel cycle is particularly effective for :

  • Establishing a culture of continuous improvement.
  • Encouraging a scientific approach to problem solving.
  • Increasing the effectiveness and efficiency of organisational processes.

What is the purpose of the Deming wheel?

The objective of the Deming wheel, also known as the PDCA cycle (Plan-Do-Check-Act). is to introduce a continuous management method for improving processes and products in an organisation. This cyclical method aims to :

  • Encourage continuous improvement: By repeating PDCA cycles, organisations can constantly look for ways to improve. By adjusting processes based on feedback and data collected.
  • Optimising processes: It helps to identify inefficiencies and develop solutions to eliminate them. This increases overall efficiency.
  • Foster a culture of learning and innovation: The cycle encourages learning from mistakes and successes. By incorporating lessons learned for future projects or cycles.
  • Reduce costs and improve quality: By refining processes and eliminating errors. Organisations can reduce costs and improve the quality of their products or services.

In short, the Deming Wheel is designed to help organisations become more competitive and efficient. Through a structured and disciplined method of continuous improvement.

How do you complete a PDCA?

To complete a PDCA cycle effectively, follow these steps:

  • Plan: Clearly define your objective. Analyse the problem by collecting data and propose potential solutions.
  • Do: Implement the chosen solution on a small scale. Document each stage to track progress and any difficulties encountered.
  • Check: Assess the results achieved against the objectives set. Use statistical tools to measure effectiveness.
  • Act: Based on the results, standardise the solution or, if it fails, adjust your plan and repeat the cycle.

Make sure you maintain rigorous documentation at each stage to enable accurate analysis and adjustments.

What is the difference between PDCA and the Deming wheel?

The terms “PDCA” and “Deming wheel” often refer to the same continuous improvement methodology. But there is a subtle distinction in their origin and use:

PDCA (Plan-Do-Check-Act)

This model was originally developed by Walter A. Shewhart, a statistician at Bell Laboratories in the 1920s. It is a four-phase iterative model designed for the control and continuous improvement of processes and products. PDCA is a quality management tool that helps organisations test hypotheses through controlled experimentation. Analyse the results and adjust processes before implementing them on a larger scale.

Deming wheel

W. Edwards Deming, who popularised the PDCA cycle in Japan in the 1950s, modified Shewhart’s approach slightly. Deming preferred to use the term “Plan-Do-Study-Act” (PDSA). Emphasising study rather than simply checking. This reflects a more analytical and systematic approach to learning during the cycle. The term “Deming wheel” is sometimes used to refer to this modified model.

In practice, the two terms are often used interchangeably. Although Deming’s “PDSA” places greater emphasis on continuous learning and adaptation based on scientific data and rigorous analysis.


PDCA is more than just a method. It is a management philosophy that encourages continuous innovation and reflexivity in organisations. Whether for product development. Improving services or optimising internal processes. PDCA provides a robust framework for driving change in a structured and controlled way.