Rational Sub-Grouping

This document discusses rational sub-grouping, which is the logical division of a process into sub-processes based on distinguishing factors like time, location, processes, or people. It provides examples of how to identify if rational sub-grouping may be needed, such as through special cause variation or non-normal data. Methods for confirming the appropriate rational sub-groups are discussed, including using ANOVA and HOV tests to check for statistical differences between proposed sub-groups. Practitioners are asked to identify metrics and potential sub-grouping options for reporting within their own organizations.