In-control robustness comparison of different control charts. (September 2018)

• Record Type: Journal Article
• Authors: Abid, Muhammad; Nazir, Hafiz Zafar; Riaz, Muhammad; Lin, Zhengyan
• Is Part Of: Transactions of the Institute of Measurement and Control. Volume 40:Number 13(2018)
• Page Start: 3860
• Page End: 3871
• Publication Date: 2018-09
• Subjects: Average run length -- control harts -- CUSUM -- EWMA -- SDRL; Automatic control -- Periodicals; Measuring instruments -- Periodicals; Commande automatique -- Périodiques; Mesure -- Instruments -- Périodiques; 681.2
• DOI: 10.1177/0142331217734302
• Languages: English
• ISSNs: 0142-3312

Abstract

Control charts are widely used to monitor the process parameters. Proper design structure and implementation of a control chart requires its in-control robustness, otherwise, its performance cannot be fairly observed. It is important to know whether a chart is sensitive to disturbances to the model (e.g. normality under which it is developed) or not. This study, explores the robustness of Mixed EWMA-CUSUM (MEC) control chart for location parameter under different non-normal and contaminated environments and compares it with its counterparts. The robustness of the MEC scheme and counterparts is evaluated by using the run length distributions, and for better assessment not only is in-control average run length (ARL) used, but also standard deviation of run length (SDRL) and different percentiles – that is, 5 th, 50 th and 95 th – are considered. A careful insight is necessary in selection and application of control charts in non-normal and contaminated environments. It is observed that the in-control robustness performance of the MEC scheme is quite good in the case of normal, non-normal and contaminated normal distributions as compared with its competitor's schemes.