Alternative Designs of the Hodges-Lehmann Control Chart

Abstract

The Hodges-Lehmann control chart was proposed as a nonparametric alternative to the classical control chart. The proposed technique for establishing control limits produces control charts with in-control average run lengths (ARL₀s) quite different from the anticipated ARL₀s. In this paper two alternative methods for obtaining a Hodges-Lehmann control chart with a specific ARL₀ are provided. The first alternative modifies the method of constructing the control limits and the second alternative modifies the statistic plotted. A numerical example of the three control charts is provided. The alternative control charts and the control chart are compared in their robustness to changes in distributional form.

• Average Run Length
• Control Charts
• Statistical Process Control

Additional information

Notes on contributors

Edward A. Pappanastos

Dr. Pappanastos is an Assistant Professor of Computer Information Systems. He is a Member of ASQC.

Benjamin M. Adams

Dr. Adams is an Associate Professor in the Department of Management Science and Statistics and in the Applied Statistics Program. He is a Member of ASQC.