The active/noticeable observation approach involves the observer interacting with the subject, typically by asking questions as the work is being performed. This helps clarify steps, gather deeper insights, and validate the process as it unfolds. It contrasts with passive observation where the analyst simply watches without interrupting the workflow.
BABOK Reference - Technique: Observation (Section 10.31):
"Active observation involves asking questions throughout the observation, while noticeable observation means the subjects are aware of being observed."