Kanban guide · Lean foundations
Value Stream Mapping: How to Map and Improve Your Process
Value stream mapping (VSM) is a Lean technique for visualising every step needed to deliver a product or service to a customer, including the waiting between steps. It shows where time and effort are wasted, so you can design a better process.
Key takeaways
- VSM maps every step and wait from request to delivery.
- It measures process time, wait time and flow efficiency.
- Design a future state that removes the biggest waste.
Origins
VSM comes from Toyota's material and information flow diagrams and was popularised by Mike Rother and John Shook's 1998 book Learning to See. It is now used in software, services, healthcare and offices as well as manufacturing.
Key metrics on a value stream map
| Metric | Meaning |
|---|---|
| Process time | Time spent actively working on a step |
| Wait time | Time between steps |
| Lead time | Total time from request to delivery |
| % complete and accurate | How often a step receives work it can use without rework |
| Flow efficiency | Total process time ÷ total lead time |
How to create a value stream map
- Choose the value stream: one product, service or request type.
- Define start and end: from customer request to customer receipt.
- Walk the process with the people who do the work.
- Map each step with its process time, wait time and quality.
- Add information flows: how work is triggered and communicated.
- Calculate totals: lead time, process time, flow efficiency.
- Identify waste: long waits, rework loops, handoffs, unnecessary steps.
- Design a future state map that removes the biggest waste.
- Plan and run improvements, then map again.
Example: software change request
A team maps a change request from customer to release. Active work totals about 3 days, but total lead time is about 30 days, a flow efficiency near 10%. Most time is spent waiting for approval and for a monthly release window. The future state introduces weekly releases and a delegated approval, aiming to cut lead time by more than half. Illustrative example.
Free templates for this topic
Frequently asked questions
What is the difference between a process map and a value stream map?
A process map shows the steps; a value stream map adds time, waiting, quality and information flow, focusing on the customer's end-to-end experience.
How long does a VSM workshop take?
Often half a day to two days, depending on the complexity of the process.
What is value stream mapping?
Value stream mapping (VSM) is a Lean technique for drawing every step, hand-off and wait involved in delivering a product or service, so you can see and remove waste.
Who created value stream mapping?
It comes from Toyota's material and information flow diagrams and was popularised by Mike Rother and John Shook's 1998 book Learning to See.
What are the steps of value stream mapping?
Choose a product or service, walk the process, map the current state with process and wait times, identify waste, design a future state and create an improvement plan.
What is a current state value stream map?
A map showing how the process works today, including each step, its process time, waiting time between steps and information flows.
What is a future state value stream map?
A map of the improved process the team aims to reach, with waste removed and flow improved, used to plan specific changes.
What data do you collect for a value stream map?
For each step: process time, waiting time, rework or defect rates, number of people involved and hand-offs. Totals give lead time and flow efficiency.
What symbols are used in value stream mapping?
Standard icons include process boxes, inventory triangles, push arrows, supermarkets, kanban signals and a timeline along the bottom. Simple boxes and arrows are fine for knowledge work.
Can value stream mapping be used in software development?
Yes. Software teams map the path from idea to production to find delays in approvals, testing and deployment, often feeding DevOps improvements.
How does a value stream map help design a Kanban board?
It shows the real stages and queues in your process, which become the board's columns and waiting stages. See Kanban boards.