iSixSigma

Process Control Plan

Definition of Process Control Plan:

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Process improvements have a tendency to slip back to how things were done, just like a stretched rubber band snaps back when released. The process control plan will help prevent this from happening. 

Let’s learn more about how that can be done.

Overview: What is a process control plan? 

The purpose of the process control plan is to be sure the process improvements made by your Six Sigma improvement team can be sustained over time. The process control plan will be developed during the Control phase of DMAIC. It is a written summary that describes what’s needed to keep your process at the improved level. 

The control plan will usually display the improved process map, key process variables, and the reaction plan if the improved process starts to degrade. 

While there are a variety of control plan formats, some of the key elements should include:

  • Process flowchart: A visual representation of the high-level process steps for the improved process.
  • Critical metrics: Key measurable characteristics of a product or process whose performance standards or specification limits must be met in order to satisfy the customer. These are often referred to as CTQs (critical to quality).
  • Measurement method: Documents the method used to collect the process measurement or CTQ.
  • Sample size: The sample size chosen for measurement.
  • Measurement frequency: Identifies how often the data should be collected.
  • Reaction plan: A documented process for correcting deviations from the desired state including the who, what, when, and where of the actions taken.

An industry example of a process control plan 

As the project team was finishing up the Control phase, the Master Black Belt assigned to the team provided a quick tutorial on how to create a process control plan. She showed them the following template as an example of how they can develop one for their project:

Process Control Plan example

Frequently Asked Questions (FAQ) about a process control plan

1. What is a process control plan used for? 

A process control plan is a written document used to sustain and maintain the gains achieved during a process improvement event. 

2. When is the process control plan developed? 

It is developed in the Control phase of the DMAIC methodology.

3. What are the major elements of a process control plan? 

The major elements of a process control plan are:

  • Process flowchart
  • Critical metrics.
  • Measurement method 
  • Sample size
  • Measurement frequency
  • Reaction plan
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