Beyond simply pigeonholing individuals into convenient categories, measuring personality traits can be thought of as having two larger purposes. One is to predict behavior. Another is:

To understand behavior  

Explanation:

Pigeonholing is used to categorize and classify different and large number of personalities and entities into small groups and clusters. And two main reasons of this categorization is to predict and understand behavior.  Through this categorization it become easy to divided different personality.    

answer; informal criminal justice process;