Im trying to find a formula that will calculate and tally how many personnel
are qualified in certain tasks that are only certfied for a period of time.

I have a list of all personnel and when they were certified on particular
tasks, but as time goes on, they will become uncertified...for example a
certification may only be good for 12 months and then have to be repeated.

Is there a formula that i can use that will tally how many are current and
certified and/or how many are not....?