Abstract

The Shewhart control chart, combined with appropriate runs rules, is a common form of statistical process control. Runs rules aid troubleshooting, giving information about the state of the process when it goes out of control. Proper use of a Shewhart control chart requires the quantification of causes and effects of failure. The example of Douwe Egberts, a Dutch tea and coffee manufacturer/distributor, demonstrates how run rules and a Shewhart control chart can be used as an effective statistical process control tool.