How to Create a Six Sigma Control Chart in Excel

A control chart was created by Walter Shewhart in Bell Labs in the 1920s to help show variations in a process over the course of a certain amount of time. They are used to help enhance product reliability. If a process is "out of control", the process may have changed over time. This is where your control chart comes into play. You can track your variability and find out if there's any special cause causing this variation.

For more information on control charts, read DMAIC Phase 5: Control by Heidi Wiesenfelder.

Excel can assist you with creating your chart. QI Macros SPC Software ($139 online) for Excel allows you to easily create your own control

chart. But, you need to know which control chart to use since there are so many. Once you have figured out which chart that you need to use, simply follow the below steps to create your chart.

1. Choose the data that you want to compare.

2. Select the type of chart that you wish to use from the pull-down menu.

To learn more about data variation in six sigma, read Understanding Variation: Common Cause & Special Cause by Heidi Wiesenfelder.

If you need to change the rules for your chart, this can be easily done by following the below procedures.

1. Go to your QI Macros menu.

2. Click Control Charts and then Control Chart Rules.

3. Pick which rules apply to what you are doing. It may take a few minutes to update the rules file.

4. Run your selected chart.

For a glossary of six sigma terms, read Natasha Baker's article Six Sigma Glossary.

Your rules should have automatically applied. But, you can check to see whether or not they did by following these steps.

1. Go to the QI Macros menu.

2. Click Control Charts and then Control Chart Rules.

3. Next go to Show Current Rules.

Your new rules should show up in the column labeled "n(points)". This means that the rules are active. These rules are now permanent. They won't change if you open and close Excel.

You can also create your own customized rules in QI Macros 2007. To create your own rules, follow the below steps.

1. Open your Excel program.

2. Go to C/Program Files/Microsoft Office/Office (10, 11,12)/XLStart/QI Templates to open to the Control Chart Rules.

3. You need to unhide the file to see it. Follow these instructions to do this Excel 2003.

(a) Go to Window.

(b) Select Unhide.

(c) Then select the Control Chart Rules file.

4. To unhide the file in Excel 2007, just go to View, and Select Unhide.

5. Once you have finished your changes, you need to save your Control Charts Rules file.

6. Re-hide the file, and click close.

7. Re-open your Excel file.

You need to close and reopen Excel for your changes to take effect.

If you prefer not to show the 1-2 sigma lines, you can turn them off. To do this, do the following.

1. Go to your QI Macros.

2. Click Control Charts.

3. Go to the Control Chart Rules.

4. Select Show Don't Show 1-2 Sigma lines.

For some useful six sigma templates, read 10 Free Six Sigma Templates You Can Download by Michele McDonough.