A critical note on memory‐type charts with the Brownian statistic

Abstract

In the paper, we conduct an assessment of the conditional expected delay (CED) profiles of the EWMA, CUSUM, and dual CUSUM charts based on a statistic linked to Brownian motion. The study reveals a noteworthy observation: the CED curves for these control charts may exhibit an increasing trend over time. Moreover, in a steady‐state scenario, it becomes evident that these control charts could be outperformed by their established counterparts.