Robust CUSUM Control Charting

Cumulative sum (CUSUM) control charts are very effective in detecting special causes. In general, the underlying distribution is supposed to be normal. In designing a CUSUM chart, it is important to know how the chart will respond to disturbances of normality. The focus of this article is to control the location parameter using a CUSUM structure and the major concern is to identify the CUSUM control charts that are of more practical value under different normal, non-normal, contaminated normal, and special cause contaminated parent scenarios. In this study, we propose and compare the performance of different CUSUM control charts for phase II monitoring of location, based on mean, median, midrange, Hodges-Lehmann, and trimean statistics. The average run length is used as the performance measure of the CUSUM control charts.