Determining measurement error requirements to satisfy statistical process control performance requirements

Abstract

Measurement error (ME) is a source of variation that may considerably affect the performance of control charts applied within a statistical process control scheme. While the consequences of ME on the actual performance of various control charts has been studied in recent publications, the more important inverse problem of how to specify ME requirements to achieve desirable control chart performance characteristics has not been addressed in the literature. In this paper, we develop guidelines regarding the formulation of specification limits to distribution-related ME characteristics. Both the Shewhart X control chart and the S ² control chart are addressed. The main results of this paper are delivered in the form of expressions, from which permissible values for measurement-error bias and the standard deviation, required to achieve specified average run length characteristics, may be easily identified. Some related issues are addressed.

Acknowledgements

The author is indebted to Prof. Eliahu Gertsbakh, who has inspired me to develop the ideas introduced here, and encouraged me to produce this paper. This work was partially supported by the Paul Ivanier Center of Robotics at Ben-Gurion University