Four numbers that matter.
The Kanban Guide names four flow metrics. Together they tell you how work actually moves, with no estimates needed.
WIP
Work In Progress
Items started but not yet finished.
Throughput
Finished Per Week
How many items finish in a period.
Cycle time
Start To Finish
How long each finished item took.
Work item age
Still Going
How long in-progress items have been going.
Source: Kanban Guides: The Kanban Guide ↗
Four numbers tell you how work really flows.