Definition:Cusum Chart

Definition

A cusum chart is a control chart designed to detect departure from acceptable operating standards.

A record is kept of the sum of deviations from an ideal target value for successive samples.

While the process is in control, the cumulative sum of deviations should remain small, because positive and negative deviations are expected to cancel each other out.

Hence, a run of samples in which either positive or negative deviations dominate indicates that the process may be out of control.

Cusum charts are specifically designed so as to make it easy for operatives to make a routine decision as to whether the process is out of control.

Also see

• Results about cusum charts can be found here.

Linguistic Note

The term cusum chart derives from an abbreviaton of cumulative sum.

Sources

• 1998: David Nelson: The Penguin Dictionary of Mathematics (2nd ed.) ... (previous) ... (next): cusum chart
• 2008: David Nelson: The Penguin Dictionary of Mathematics (4th ed.) ... (previous) ... (next): cusum chart