On developing an exponentially weighted moving average chart under progressive setup: An efficient approach to manufacturing processes—Discussion

Abstract

AbstractA mixed exponentially weighted moving average (EWMA)–progressive mean (PM) control chart (regarded as MEP) has been recently proposed in the literature for monitoring the process mean. Unfortunately, the variance of MEP statistic is incorrect. In this article, we provide the correct variance of charting statistic along with the corresponding control limits and we also evaluate the run‐length characteristics of the MEP chart. A comparison study with existing control charts indicates that the MEP chart is more effective for small to moderate process shifts. However, the PM, which is a special case of it, and the EWMA charts outperform the MEP chart in detecting small to moderate and large shifts, respectively.