Characteristics of the EWMA

The EWMA methodology has some very attractive properties, in particular:

·    Unlike traditional "Shewhart" control charts, which use each data point independently, EWMA charts may use all of the data collected over time to determine the control status of a process.

·    The EWMA is often superior to the CUSUM charting technique for detecting "larger" shifts in the process location.

·    You can use the EWMA to monitor both process standard deviations and averages.

·    You can use EWMA schemes to forecast values of a process mean.

·    You can choose weights for EWMA and the number of s for calculating control limits to match in-control average run lengths for traditional "Shewhart" control charts.