'Conversation Handle Time', or 'CHE', is a metric that compares the total actual time spent on conversations against the total output time those conversations equated to using their respective ITTs.
Calculation:
CHE = Conversation Output Hours / Handle Hours
Where the standard 'Contribution' metric includes Idle time, 'CHE' excludes it to provide agents and leaders visibility into the efficiency of their conversations.
This metric can be found in the Queue Performance table of the Contact Center Overview report, and if it's not automatically appearing when you view the table simply click on the icon in the top-right:
Choose how you'd like the table grouped:
Then select/deselect the columns you want displayed and hit 'Save':
You'll then see the columns appearing in the table in the order you selected them: