AHT- Average holding Time

Average Hold Time, or AHT, refers to the average length of time between the moment a caller finishes dialing and the moment the call is answered or terminated. The formula for measuring AHT is the total call time divided by the amount of calls. To achieve a realistic AHT figure, the ITU recommendation is that the AHT calculation be based on trace samples ranging from 15 to 60 minutes.- Webopedia

watching agents while on call...