I believe I have found the answer to this..
For each contact service queue, displays the number of calls handled, abandoned, and dequeued.
Handled: A call is considered to be handled when an agent picks up the call.
Abandoned: A call is considered to be abandoned if the call disconnects before connecting to an agent (ex. Caller hangs up)
Dequeued: A call is considered to be dequeued from a particular contact service queue if the call is handled by an agent in another contact service queue. This situation can occur when a call is queued for more than one contact service queue.