Run Stability Analysis on Control Charts

Re-analyze Stability After Changing Control Chart Data

It's easy to run stability analysis on a control chart created using QI Macros. The process is different depending on how you create your control chart:

Control Chart Created Using a Macro

  1. When you run a chart using a macro from the QI Macros pull down menu, QI Macros will automatically run stability analysis on your data and turn any unstable points or conditions red.

    Stability Analysis Example
  2. If you add datadelete a pointghost a point, or show a process change on a control chart you should re-run stability analysis on your data. To do this, click on the QI Macros Chart Menu and select "Analyze Stability."

    analyze stability on a control chart

Analyze Stability Green Up or Green Down

A customer requested the ability to show "good" rule violations in Green depending on whether "up" (higher) is better or "down" (lower) is better. To use this stability analysis tool, click Green Up or Green Down.

Control Chart Unstable Conditions in Green if moving in the desired direction

Show/Hide Stability Rule Numbers Violated

You can also show the specific rules violated.

show hide control chart rules that cause an unstable trend

To view the rules and corresponding rule numbers, click on QI Macros, Control Charts, Control Chart Rules and then Show Current Rules. A spreadsheet with the stability analysis rules will open

Control Chart with Stability Rules Violated

Clear Stability Analysis

And you can clear stability analysis which will result in all or the data points and lines being shown in blue.

Control Charts Created with a Control Chart Template

To run stability analysis on a chart created using a control chart template:

  1. Click on the chart and a shadow will appear around the edges and the chart tools menu will appear in the top right corner of the menu.

    chart menu

  2. Click on QI Macros chart menu and select Analyze Stability.
  3. If you have an X and an R chart you will need to select each chart and run stability analysis on each separately.

Learn More...

Check out our other QI Macros and Control Chart Articles for more information about using QI Macros and Excel.

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