A Performance Analysis of Hotelling's χ² Control Chart with Supplementary Runs Rules

Abstract

Hotelling's control chart is widely employed to control several related characteristics of a process because of its simplicity. However, it has little power when detecting small or moderate process shifts. The use of supplementary runs rules is described in this article showing the average run length improvements achieved and the runs rules appearance frequency.

Keywords:

• Multivariate control
• Hotelling's χ² control chart
• Supplementary runs rules
• ARL improvement

Acknowledgment

We thank the Foreign Language Co-ordination Office at the Polytechnic University of Valencia for their help in translating this article. The authors express their thanks for the helpful insights provided by the referee. In addition, the authors acknowledge the financial support of the Ministry of Science and Technology of Spain, Research Project Reference DPI2002-03537.