Who is responsible for defining metrics for change management?

In ITIL, the process owner is accountable for the overall design, performance, integration, and improvement of a single process. Defining metrics is a core responsibility of the process owner because they are accountable for ensuring the process achieves its intended outcomes. This distinguishes the process owner from the process manager, who handles day-to-day execution.

The CAB is an advisory body that evaluates and approves changes, not a governance role responsible for defining process performance metrics.

The service owner is accountable for a specific IT service end-to-end, not for the internal metrics of a supporting process like change management.

The CSI manager drives improvement initiatives across the organization but does not define the baseline metrics for individual processes - that responsibility sits with each process owner.