Individual & Range
Individual and Range Control Chart

The Individual and Range chart provides a graph of the actual readings of a process characteristic and the range extent. The Individual chart gives a picture of how well a process is centered and if it is stable. Individual are plotted in subgroup fashion with all individual data points displayed. Individual and Range charts are used for low volume processes or where few measurements are available.

The Range chart indicates the range of the actual plotted as a subgroup. The Range chart gives a picture of the change in variability. A stable process will have a fairly uniform range, while an unstable process will exhibit significant changes in the range.