Measuring risk means walking a thin line. Balancing what is highly unlikely from what it totally impossible. Financial institutions need to be prepared for the highly unlikely but must avoid getting sucked into wasting time worrying about the totally impossible.
Here are some sins that are sometimes committed by risk measurers:
1. Downplaying uncertainty - Uncertainty increases when loss size increases. Do your users know that?
2. Comparing incomparables - Do you add together numbers from di