Measures Of Population Stability and Instability

Abstract

PSI measures distribution stability of a variable. A popularly used PSI is undesirable. Creating binned ranges for its calculation is a chore. The range boundaries and the number of bins could affect the PSI quantity. Bin ordering makes no difference thus all variables are treated as categorical. We build our PSI without requiring binning, distinguishes numeric shifts from categorical redistribution, and create a mechanism to unify the two for mixed ordinal/categorical variables.