Comparing text columns

I have weekly employee lists of names for each weekly pay period. I am trying to compare the lists to see which names are new from week to week. How do I do this?

When a new employee is added to the list, have something in excel to record the date that this entry was made. When checking 'who's new?' on the sheet, check all entry dates that are within a week old. Those would be your
new entries of the last 7 days.