A Critical Note on the Partitioned Weighted Moving Average Control Chart

ABSTRACT A partitioned weighted moving average (PWMA) chart has been recently introduced for monitoring the mean of a normally distributed process. In this paper, the performance of the exponentially weighted moving average (EWMA) and PWMA charts is reevaluated in terms of the conditional expected delay metric. We show that an EWMA chart may outperform the PWMA chart when detecting delayed shifts in the process mean.