What is cusum charts?

A cusum chart is a type of control chart that is used to monitor the performance of a process or system over time. It is a graphical representation of the cumulative sum of deviations from a target or reference value. Cusum charts are primarily used to detect small, gradual shifts in the mean or level of a process.

The chart plots the cumulative sum of deviations from a target or reference value over time, taking into account both positive and negative deviations. The reference value is typically the desired level of the process, and the chart is constructed by monitoring the deviations from that value.

Cusum charts are useful for detecting changes in a process that are not easily detectable using standard control charts. They are particularly useful for monitoring a process that has a gradual change or drift, rather than sudden changes or shifts. The chart is constructed by calculating cumulative deviations from the target value and plotting these values against time.

Using cusum charts can help organizations identify problems early, before they become significant enough to affect the quality of the product or service. They can also be used to identify the root cause of problems in a process, allowing organizations to take corrective action and prevent future problems from occurring.