Kanban guide · Flow and metrics
WIP Aging Chart: Spot Stuck Work Before It's Late
Cycle time tells you about items you have already finished. Work item age tells you about items still in progress. A WIP aging chart puts every unfinished item on one chart, so you can act before an item becomes late.
Key takeaways
- A WIP aging chart plots unfinished items by stage and age.
- Compare ages with historical cycle time percentiles.
- Act on old items first in the daily meeting.
What the chart shows
The horizontal axis lists the workflow stages; the vertical axis shows age in days. Each in-progress item is a dot in its current stage, at the height of its age. Background bands show historical cycle time percentiles, for example the 50th and 85th.
How to read it
- Dots below the 50th percentile: on track.
- Dots approaching the 85th percentile: at risk; discuss today.
- Dots above the 85th percentile: already slower than most past items; act now.
- Old dots in early stages: items that started and stalled.
Using it in the daily meeting
- Start with the oldest items, especially those nearing your service level expectation.
- Ask what is needed to move each one forward.
- Swarm, unblock or split items where needed.
- Avoid starting new work while old items are at risk.
Why work item age matters
Age is a leading indicator: it warns you while there is still time to act. Combined with a service level expectation, it turns Kanban from reporting what happened into managing what is happening.
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Frequently asked questions
What is work item age on a WIP aging chart?
The time since an unfinished item started, measured from the same start point used for cycle time.
How is a WIP aging chart different from a cycle time scatterplot?
The scatterplot shows finished items; the aging chart shows unfinished ones.
What is a WIP aging chart?
A WIP aging chart shows every item currently in progress as a dot, placed in its workflow stage and plotted by how long it has been in progress.
How do you read a WIP aging chart?
Look for dots approaching or above your 85th percentile cycle time line, and for old dots stuck in early stages. Those items need attention first.
Why is a WIP aging chart a leading indicator?
Because it plots work item age, which warns you about items at risk while they are still in progress, before they finish late. Cycle time only tells you after the item is done.
How is work item age calculated for a WIP aging chart?
Age = today's date − start date for each unfinished item, using the same start point as for cycle time.
What should a team do when the WIP aging chart shows an ageing item?
Discuss it at the daily meeting, swarm on it, remove the blocker or split it. Starting new work should wait until it moves.
What are the percentile lines on a WIP aging chart?
They show historical cycle time percentiles, such as the 50th and 85th, so you can see whether an item is already taking longer than most past items.
Which tools produce a WIP aging chart?
Several Kanban tools and analytics add-ons produce one, and you can build a simple version in a spreadsheet from start dates and stages.
How often should the WIP aging chart be reviewed?
Daily, ideally at the daily Kanban meeting, because its value is in catching stuck work early.
How does a WIP aging chart relate to service level expectations?
The service level expectation acts as a threshold: items nearing it are at risk of missing it. See Kanban planning.