The everyday problem
A team may feel that a new process is faster without knowing which part improved. Changes in workload or case mix can obscure the effect. A baseline helps the team separate a real operational improvement from a different set of work arriving during the pilot.
A practical approach
Record task definitions, volume, elapsed time, and exception types before the change. Use the same definitions afterward and note important differences in the workload. Pair speed with a quality check so that faster completion does not merely move rework downstream.
Try this with your team
Create a baseline worksheet for one task with volume, time, rework, and exception fields. Agree who will collect each measure and how often it will be reviewed.