Is a candidate’s personality static and unchangeable?

Heck no! Although it is rare for a dramatic change to occur, it is more usual for some scores to drift over time based on environment, skills developed, and behavior (it’s a feedback loop!). For this reason, we do not recommend using test results that are more than 2 years old. People change and we have found that after 2 years that ‘drift’ is too much to reliably predict behavior.