When he created control charts in the 1920’s, Walter Shewhart was concerned with two types of mistakes:
- Assuming common causes were special causes
- Assuming special causes were common causes
Since it is not possible to make the rate of both of these mistakes go to zero, managers who want to minimize the risk of economic loss from both types of error often use some form of Statistical Process Control.
The control bounds in SLIM-Control perform a related, but not identical function.