What is the Shewhart cycle?

The Shewhart cycle, which is sometimes known as the plan do check act (PDCA) methodology, is a four-step project management tool for implementing continuous improvement. It involves systematically testing possible solutions, assessing the results, and implementing the ones that have shown to work. It promotes testing improvements on a small scale before updating company-wide procedures and work methods.

Other names Shewhart cycle goes by include plan do study act (PDSA) cycle and Deming cycle. It is based on the scientific method of problem-solving and was popularized by Dr. W. Edwards Deming, who is considered by many to be the leading thought leader of modern quality control.

When Shewhart cycle is applied within a maintenance program, it can accelerate constant improvement and help the company optimize their processes and operations. If every step is carried out consistently and correctly, iterations can take place quicker, which means improvements happen faster.

The Shewhart cycle methodology

Here’s a breakdown of what each step in the Shewhart cycle entails:

Plan: Refers to recognizing where opportunities exist and making a plan to implement change. In a manufacturing setting, the planning process could be to decide on what operational problem needs resolving or improving.

Do: Implement the change and test its effectiveness. The ideas, methods and/or process improvements in the plan must now be put into place. This may include changes to production processes, maintenance strategies, implementing training or changing work practices.

Check: Review the test, measure and analyze the results, and evaluate the lessons learned. Data such as production output, machine availability and safety statistics should be measured against the projected outcomes detailed in the plan.

Act: Take action towards improvement based on what you learned from the test. If the change does not work, go through the cycle again with a different plan. If the experiment was a success, incorporate what you learned from the test into wider changes. Learnings from the test can be applied to continual change, which can then be put through the Shewhart cycle again.

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Example of how to apply the Shewhart cycle

An example of how to use the Shewhart cycle is within inventory management. It’s easy for inventory to be misplaced or go missing, or not know how many spare parts you have on hand for each asset. The Shewhart cycle can help you optimize the way you store and organize your inventory.

You can implement a test by creating a detailed procedure and checklist for how items should be documented when they arrive in the facility and where they should be stored. Evaluate each step of the procedure and see where any communication gaps may lie between employees responsible for each step, or if there is a lack of clarity in how the steps are laid out within the instructions and checklist. Keep iterating until all stakeholders are satisfied with the new procedure for documenting new inventory, and create a plan for rolling it out to the rest of your inventory.

What’s really useful about the Shewhart cycle is that it gives you actual, verifiable results instead of having to guess. It also allows you to easily modify each aspect of your operations until you’ve achieved the desired result. The Shewhart cycle enables you to focus on implementing actual improvements instead of having to spend so much time analyzing the situation and assessing the risk from each change.

The Shewhart cycle is a process for identifying and correcting problems in production

The Shewhart cycle is a very important tool to use in the process of improvement. It helps you identify your process, break it down into smaller steps, and then put those steps together to form an improvement plan. The cycle also lets you keep track of where you are at in the process so that you can make sure everything is going as planned.

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