Which control chart would you see to track the rejections in maintenance project when bugs arrival patterns are not constant?

In a scenario where the arrival patterns of bugs are not constant, an appropriate control chart to use would be the Cumulative Sum (CUSUM) control chart. This chart is useful for detecting small shifts in the process mean over time, making it suitable for tracking rejections in a maintenance project where bug arrivals may vary unpredictably. Additionally, the Poisson control chart could also be considered if the data on bug arrivals is count-based and follows a Poisson distribution.