Run and control charts

What is it?

  A run chart is a simple graph for monitoring a process or activity..

A control chart has statistically determined action lines added. The line is used to give a clear indication of when the process needs investigating.

When to use it

  • Gathering data
  • Analysing data
  • Implementing and testing solutions
  • Ensuring continuous improvements

What does it achieve?

A run chart is used to monitor a process, so any trends or runs can easily be seen.

By adding a predetermined action line, the process can be monitored to see if it is within the preset limit.

Run chart summary

To construct a run chart you must know:

  • What is the problem
  • What data is required
  • Where is the data collected
  • When is the data collected
  • How is the data collected
  • How to choose the scale for the X and Y axis

Control chart summary

Control charts are used to monitor a process within preset limits, these limits can be:

  • Design specifications
  • The standard deviation of the sample data
  • The average sample X and average range R
  • Limits fixed by law or economics
  • Investigation is required when:
    • 1 point goes past the action line
    • 2 points go past the warning line

Typical control chart