QI Macros Control Chart Menu

Show Process Change on Control Charts

It's easy to show process changes on a control chart created by QI Macros. The process is different depending on how you create your control chart:

New Charts Created with a Macro

To calculate two or more sets of control limits on new charts simply leave a blank row between the data points where you want the limits to change:

blank row to designate process change

Select the data including the blank row(s) and run the chart. You should get a chart with two or more sets of control limits:

control chart with a process change using QI Macros

Existing Charts Created with a Macro

Show Process Change on Control Chart Tutorial Video

  1. Go to the chart and click on the first data point where the process change occurred. Note: The first time you click on the point, Excel will select the whole line. Click on the point a second time to get just the point:
    select a point to show a process change on a control chart created using QI Macros
  2. Click on the QI Macros chart menu and select Show Process Change:
  3. show-process-change

  4. The macros will calculate a new set of control limits starting at the data point you selected.  Note: you can do this more than once on a chart. The example below shows three separate sets of control limits:

  5. Don't forget to rerun stability analysis using the new control limits. Click on the chart sheet. Use the QI Macros pull down menu to select "Analyze Stability With Control Chart Rules." QI Macros will rerun stability analysis using the new control limits.

  6. Note: Performing these steps on an X chart will not update the R chart. You will need to update the R chart separately.

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