Control Chart versus Run Chart in Quality Control

Control Chart versus Run Chart in Quality Control infographic
Control Chart versus Run Chart in Quality Control infographic

Control Chart versus Run Chart

If you are preparing for the PMP Certification exam, most probably you asked the following questions yourself- What is the purpose of a control chart ? or What are the types of control charts? Basically, Control Chart and Run Chart are two essential Quality Control tools. Both of them are used for evaluating and analyzing quality results within a project or a process. When you look at these charts,  you will have an insight regarding the health of the process. However, a lot of people mix up these two different tools for quality control and mistakenly think that they are interchangeable. This article will try to explain the similarities and differences between them.

There are seven tools for Quality Control which are below;

– Check sheet
– Control Chart
Fishbone Diagram (Cause-and-effect diagram)
– Flowchart
– Histogram
Pareto chart
Scatter diagram

They are also known as “The Old Seven” or “The Basic Seven.”

Run Chart



A run chart is a simple chart shows data points over a period of time. The displayed data in a run chart mostly show trends, the performance of manufacturing, etc.
A run chart helps you analyze the following over time:
– Changes or trends of the process
– The cycle of the process
– Performance of a process

Note that Control Charts provide more specific information and understanding of the process rather than the Run Charts.

Benefits of Using a Run Chart



The following are a few benefits of a Run Chart:

  • It is a visual tool which is easy to draw and use.
  • It enables to determine the performance of a process easily
  • It does not require too much technical skills.
Run Chart
Run Chart

Control Chart



A control chart is a specific type of graph shows data points between upper and lower limits over a period of time. You can use it to understand if the process is in control or not. These charts commonly have three types of lines such as upper and lower specification limits, upper and lower limits and planned value. By the help of these lines, Control Charts show the process behavior over time.

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Benefits of Using a Control Chart



The following are a few benefits of this chart:

  • It enables to specify the stability of a process.
  • It enables to specify the regions where the quality needs to be improved or where the corrective actions need to be taken.
  • It enables to analyze the variations between the given limits

Summary



Both Control Charts and Run Charts are generated by placing the data within a given period. You can obtain a lot of information when you look at them. However, Control Charts include upper and lower control limit lines. Depending on the targets of the project, the most suitable chart should be selected. Generally, they give more specific information and understanding of the process, compared to the Run Charts.

Note that these charts are essential communication tools for the project manager. If you want to add or share anything, you can use the comments section below to do so.

See Also

Grade and Quality

External Reference

7 Basic Quality Tools

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