shows that the simple 2
2 runs rule PEWMA chart is
the least performing chart in detecting decreases in the Poisson
process mean shift. The proposed chart outperforms all other
charts we investigated except in a very small region when the
mean shift is less than one. In Figs. 2 and 3, the classical
PEWMA is less effective than other charts. Overall, the
proposed chart provides the best sensitivity to decreases in the
Poisson mean processes.