This metric gives you the option to quickly see how many private comments each of your agents are making per hour, on average.
(Private Comments) / (Time on Ticket) = Private Comments per Hour
Example: Agent A has made 26 private comments and his time on Tickets was 2h30min (after making a conversion to decimal it is 2.5h) putting this into the formula we will get 26/2.5=10.4 Private Comments per hour.