This metric will track the total amount of time a ticket is assigned to an agent up until the ticket is solved. After it solved the timer does not run. If it is re-opened then the timer starts running again from the time it is reopened. Please note that this is real time and does not indicate the time the agent is actively on the ticket.
Ticket is assigned to Agent A @ 10 AM
Agent A assigns ticket to AGENT B @ 12 PM
Agent B Assigns Ticket back to Agent A @ 2PM
Agent A Solves ticket at 4PM
AGENT A Assigned Ticket Time = 4 hours (10am-12pm + 2pm-4pm)
AGENT B Assigned Ticket Time = 2 hours (12pm-2pm)
You are able to view this metric from your Summary Report and can view the Assigned Ticket Time by agent or group.