Kanban guide · Flow and metrics
Flow Efficiency: How Much of Lead Time Is Real Work?
Flow efficiency measures how much of the time an item spends in your process is spent actively working on it, rather than waiting. It often reveals that the biggest delays come from queues, not from slow work.
Key takeaways
- Flow efficiency is active time divided by total time in process.
- Most delay usually comes from waiting, not working.
- Lower WIP and fewer handoffs improve it.
Formula
Flow efficiency = active work time ÷ total time in process × 100%
Why it is often low
In many knowledge-work processes, items spend most of their time waiting: for review, for approval, for another team or for someone to have capacity. Flow efficiency well below 50% is common. That's good news, because reducing waiting is often easier than making people work faster.
How to measure it
- Split board columns into "doing" and "done/waiting" sub-columns.
- Mark blocked time on cards.
- Compare time in active columns with total cycle time.
- Sample a set of recent items if your tool can't calculate it automatically.
How to improve flow efficiency
- Lower WIP limits so items wait less in queues.
- Reduce handoffs between people and teams.
- Agree fast-turnaround policies for reviews and approvals.
- Remove recurring blockers; see blocker clustering.
- Map the end-to-end process with value stream mapping.
Free templates for this topic
Frequently asked questions
What is a good flow efficiency?
There is no universal target. Measure your baseline and aim to improve it; many teams find large gains simply by reducing waiting.
Is flow efficiency the same as resource utilisation?
No. Utilisation measures how busy people are; flow efficiency measures how continuously work moves. High utilisation often lowers flow efficiency.
What is flow efficiency?
Flow efficiency is the share of an item's total time in process that is spent actively working on it, rather than waiting.
How do you calculate flow efficiency?
Flow efficiency = active work time ÷ total time in process × 100%. For example, 2 days of work in a 10-day cycle time gives 20%.
Why is flow efficiency often low?
Items spend most of their time waiting: in queues, for reviews, approvals or other teams, or blocked. Multitasking also adds waiting time.
How do you improve flow efficiency?
Reduce WIP, shorten queues, cut hand-offs, resolve recurring blockers and bring needed skills into the team. Start by removing the longest waits.
How do you measure active work time for flow efficiency?
Track when items sit in active versus waiting columns, or mark cards as blocked or waiting. Digital tools can sum time per column automatically.
What is the difference between flow efficiency and cycle time?
Cycle time is the total elapsed time to finish an item. Flow efficiency shows what proportion of that time was active work.
Is high flow efficiency always good?
Usually, but chasing very high numbers can mean people sit idle waiting for work. The aim is to cut waiting for the work, not to keep people busy.
Does value stream mapping measure flow efficiency?
Yes. A value stream map records process time and waiting time at each step, which gives the same ratio across the whole process.
Why do waiting columns matter for flow efficiency?
Separate waiting columns, such as "Ready for review", make queue time visible on the board so you can measure it and act.