The coefficient of variation chart based on median run length

Abstract

This study suggests a design of the coefficient of variation (CV) chart based on the median run length (MRL). The run length distribution of the CV chart changes from highly skewed when the process is in-control to nearly symmetric when the process is out-of-control at the larger shifts. Therefore, the MRL can be used as an appropriate performance measure to provide a meaningful information for the performance of the CV chart. The procedure for the design of the CV chart based on the MRL will be provided. An industrial example is provided to illustrate the implementation of the CV chart.