The Deming Cycle (PDCA) and the constant improvement of quality

deming cycle

Analizing the quality and trying to improve it, is probably the main purpose behind improving business processes.

This philosophy of process improvement comes from a very important person, William Edwards Deming, a statistician, often defined as a philosopher of science.

Deming’s goal was to reapply the scientific method to business processes, which he actually did with the so-called Deming Cycle, or PDCA.

Deming’s approach is not just about improving processes, but can also be about improving an entire organization in general.

What is the Deming Cycle

The Deming cycle is a model of continuous quality improvement which consists of a logical sequence of four key phases:

  • P – Plan, or planning
  • D – Do, or the execution
  • C – Check, ie the test and control
  • A – Act, which is the action

Deming’s experience as an engineer gave him an overview of industrial processes and the real attempt to standardize operations in order to ensure large-scale operation.

By studying mathematical physics, he found himself in a position that allowed him to contribute to the growing science of statistics.

Deming’s sampling techniques, for example, are still in use in the US Census Department and the Bureau of Labor Statistics.

The key points on which Deming was working are:

  • Having a system for continuous quality improvement
  • Reducing errors and defects through higher levels of quality uniformity
  • Understanding the meaning of quality in the context

the deming cycle

Let’s look at the four phases of the Deming Cycle in detail.

The phases of the Deming Cycle: Planning

The first goal of the Deming Cycle is to plan ahead in order to understand what you want to achieve based on the expected results. It is a both practical and theoretical step.

Here, we are dealing with business processes, where we intend to improve something within the organization.

At this stage, you will have to test and analyze what is currently wrong with the product or process and how this can be improved.

Also here, one tries to understand what changes can be made to tackle the problems or to achieve something better.

 The phases of the Deming Cycle: Execution

Execution begins first with a small-scale test and in a limited context.

Here, the changes are implemented to test the different variables and each step will be documented.

Instead of simply deciding to make a change and suddenly reviewing all the operations, it is essential to make changes slowly and iteratively during the hypothesis test.

The use of studies that can be measured with respect to control groups, allows to better understand the data received, allowing not only to improve the output, but to understand exactly why the output has been improved by the changes made.

For Deming, this phase should be like a model of a scientific experiment.

The phases of the Deming Cycle: Test and Control

In this phase, the results and findings are studied and collected.

For Deming, the results of the planning and execution will be shown at this stage.

Do the results coincide with the forecasts? In what ways do the results differ, and why?

This phase of study should teach us to draw conclusions exactly like a scientist does after an experiment. Instead of simply asking the question “Did it work?”, for Deming you will have to ask “Why did it work?”.

The phases of the Deming Cycle: Action

This phase is the final one of the process and the first phase of the next cycle.

Here, the recommended changes have been implemented and the process is finalized. Now that we have learned that the output can be generated by executing action X, this action will be performed in each relevant situation.

This phase can include both the implementation of improvements in the company as well as the implementation of new knowledge within the organization.

Just as the results of repeated experiments create new useful knowledge, so these business results must be incorporated into new premises from which the cycle can be restarted.

The company continues to go through the cycle until the expected and actual results coincide and no further changes are necessary.

 The pros and cons of the Deming Cycle

The Deming Cycle is a simple but powerful way to solve new and recurring problems in any sector or process.

Its iterative approach allows the project manager and his team to test solutions and evaluate results in a quality improvement cycle.

The Deming Cycle establishes a commitment to continuous improvement, however small, and can improve efficiency and productivity in a controlled way, without the risk of making untested large-scale changes.

However, going through the Deming Cycle can be much slower and more time-consuming than a direct implementation.

For this reason, it may not be the appropriate approach in the case of an urgent problem or an emergency.

Moreover, this methodology requires significant “buy-in” by team members and offers fewer opportunities for radical innovation.

For Deming, the PDCA treats process experiments as hypothesis tests by asking the questions “did it work or didn’t it work?” And “Is the hypothesis true or is the alternative true?”

This is the cycle through which an hypothesis is developed, the experiments are conducted, the results are evaluated, and the hypothesis is reviewed and repeated.

In simple words, Deming’s approach, seems to want to remove our blinders.

We need to stop looking for only minor changes to eliminate process inefficiencies and instead start thinking big about how processes can be improved in order to increase quality.

For Deming, the same levels of scientific rigor that one would expect from the best researchers should be used in business. Let’s try then.

We have the tools, we have the culture.

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