Definition of Stratification:
A technique used to analyze/divide a universe of data into homogeneous groups (strata) often data collected about a problem or event represents multiple sources that need to treated separately.
It involves looking at process data, splitting it into distinct layers (almost like rock is stratified) and doing analysis to possibly see a different process.
For instance, you may process loans at your company. Once you stratify by loan size (e.g. less than 10 million, greater than 10 million), you may see that the central tendency metrics are completely different which would indicate that you have two entirely different processes…maybe only one of the processes is broken.
Stratification is related to, but different from, Segmentation.
A stratifying factor, also referred to as stratification or a stratifier, is a factor that can be used to separate data into subgroups. This is done to investigate whether that factor is a significant special cause factor.