Work management
Cycle time, lead time and aging
Two measurements that are routinely confused, reported as percentiles rather than averages — and the one chart you can still act on.
They are different measurements
Lead time runs from when work was raised to when it was done — what the person who asked experiences, including every day it sat in a backlog nobody looked at. Cycle time runs from when work started to when it was done — what the team controls. A team that halves its cycle time while its backlog grows has not got faster from the outside, and only reporting both shows that.
Percentiles, not averages
The distribution is right-skewed. Most items finish quickly and a handful sit for months because they were blocked, deprioritised or forgotten — and one of those drags the mean past the point where any ordinary item lands. A team quoting the mean either over-promises to itself or over-quotes to a client, and both feel arbitrary.
| Figure | Read as |
|---|---|
| p50 | Usually. |
| p85 | What a forecast should be built on — the number that holds most of the time without padding for a worst case that never repeats. |
| Mean | Kept because people expect it. Its distance from p50 is the signal: far apart means a long tail. |
Finished work that was never marked started has a lead time and no cycle time. It is counted and reported rather than quietly dropped — a silent exclusion would make the cycle figure look better the less the team uses the board.
Aging work in progress
This is the one to act on. A cycle time report describes work that is already finished — it is history, and nothing can be done about it. The aging list is the same measurement applied to work still moving, so the item about to become an outlier can be noticed while it can still be helped.
An item is flagged once it has run longer than 85% of what the team has finished did. Comparing against the mean would flag half the board, and a register where everything is red is one nobody reads.