What your board is actually doing
Lead time, cycle time, throughput, a cumulative flow diagram and — most useful of all — which work on the board right now is going stale.
Lead time, cycle time, throughput and what is going stale
From dates on work items. The definitions are stated and applied consistently, because that is where flow metrics usually go wrong.
Work items
Cumulative flow
Cycle time distribution
Aging work in progress
Definitions, which matter more than the arithmetic
Lead time runs from commitment to done. It is what the person who asked experiences, including all the waiting before anyone started.
Cycle time runs from starting work to done. It is what the team controls.
The gap between them is queue time, and on most boards it is larger than the work itself.
Both count inclusively. Something started and finished on the same day took one day, not zero. A zero would claim the work took no time, which never happened.
Aging is measured from start to the as-of date for items not yet done. It is the most actionable number on the page and the one least often looked at.
Quote the 85th percentile, not the average
An average cycle time answers a question nobody asks. Nobody wants to know the mean; they want to know what to expect.
"We finish 85% of items within nine days" is a statement you can keep and a stakeholder can plan around. "Our average cycle time is five days" is true, unfalsifiable in any individual case, and quietly wrong about half the time. Cycle time distributions have long right tails, so the mean sits well below what people actually experience.
Aging work is the number to act on
Every other metric here is about the past. Aging is about items on the board right now, and it is the only one you can still do something about.
An item aged eleven days against an 85th percentile of nine is already an outlier, and it is telling you so while there is still time to intervene. Most boards discover this after the fact, in a retrospective, when the useful moment has passed.
What a cumulative flow diagram shows
The vertical distance between the committed and done lines is work in progress. The horizontal distance is approximate lead time. Bands that widen mean work is arriving faster than it leaves.
A flat done line with a rising committed line is the shape of a team being given more work than it can finish, and it is visible weeks before anyone says so out loud.