To streamline communication and clarify case conversation history for an insurance company handling a high...

To streamline communication and clarify case conversation history for an insurance company handling a high volume of cases, I recommend a combined approach utilizing Case Comments and Case Hierarchy, with careful consideration of Chatter's limitations:

A project sponsor has stated that their primary goal is to reduce the cost per case in the contact center.

Which standard metric should a consultant focus on improving to reduce cost per case in the contact center?