In one line: Map every step that delivers value to the customer, with its time, inventory and information flow, then design a future state with less waste and less waiting.
Core idea
A value stream is all the actions, both value-adding and not, needed to bring a product or service from request to delivery. Value stream mapping, popularized by Mike Rother and John Shook’s Learning to See [1], draws that stream on one page so a team can see where time goes. The usual shock is how little of the total lead time is actual work: most of it is waiting.
How it works
- Set the boundaries: which product family or service, which customer, and where the stream starts and ends.
- Walk the flow in person, following one item from end to end. Gather real data rather than estimates.
- Draw the current state:
- process boxes with key data: cycle time, changeover time, uptime, number of people
- inventory or queues between steps
- the information flow that tells each step what to do
- a timeline comparing value-added time with total lead time
- Analyze the current state: where are the queues, the push signals, the rework loops and the bottleneck?
- Design the future state:
- pace production to customer demand (takt time)
- create continuous flow where possible
- use pull where it isn’t
- level the work
- Make and track an implementation plan, then repeat the cycle.
In practice
VSM works on knowledge work as well as factories. A design process, an engineering change, a proposal or a test campaign can all be mapped the same way. Engineering value streams often show long waits for reviews, tools and test slots, plus loops where a design returns to an earlier step after a downstream check fails. Mapping a real stream with the people who do the work, rather than from the official procedure, is what makes the exercise honest.
Questions to ask yourself
- What fraction of my project’s lead time is someone actually working on it?
- Where is the biggest queue in our flow, and what feeds it?
- What would our future-state map look like if we designed for flow?
Connections
- Method home: Lean. Simpler maps: Business Process Mapping.
- Where the bottleneck is: Theory of Constraints, Throughput and Timing Analysis. Across companies: Supply Chain Management.
- Capabilities exercised: Vision, Realizing the Vision, Connecting Across Disciplines.
Sources
- The standard value stream mapping method [1]
- Snyder and Landel (2011) Business Process Mapping [2]
- Course readings on value stream mapping from an aerospace company’s lean program (proprietary; not reproduced).