Conversation so far:
what does it mean when your drawer is over
An overage is when your drawer is over the amount your POS report says you should have.
what does it mean when your cash drawer is under
A shortage is when your cash register's total is short.
why would a cash register be short
Cash register shortages could mean cash was either lost, stolen, or counted incorrectly.
who is responsible for cash register shortages
For the most part, discrepancies in cash registers arise as a result of employees making simple mistakes and not catching them in time.

Question: what is a prevention measure
Self-contained rewrite: what is a prevention measure for cash register shortages