Also called value stream map, material and information flow
What is value stream mapping?
Drawing every step a product goes through, with the waiting time between them, on one page.
What else it is called
- Other names
- value stream map, material and information flow
- In French
- cartographie de la chaîne de valeur
Related entries
Understanding value stream mapping
A one-page drawing of everything that happens to a product from order to delivery: each operation, each inventory pile, the time taken at each step and, crucially, the time spent waiting between them. It also shows how the information flows, which is where many of the delays actually originate.
What makes it worth the day it takes is the timeline along the bottom, where working time and waiting time are drawn separately and totalled. The first time a plant does this honestly the result is usually uncomfortable: a part that takes four hours of work takes five weeks to get through the building. Nobody believes that figure until they have walked the route themselves with a stopwatch and a clipboard.
Then you draw the future state, decide what has to change to reach it, and put dates against the changes. Without that last step the map is a poster.
How it is calculated
Process cycle efficiency = value-adding time ÷ total lead time
A figure under 10 per cent is normal in a plant that has never looked. It means more than nine tenths of what a customer waits for is waiting.
In practice
Walk the route yourself with a clipboard rather than pulling the times from the system. The system records the operations. The waiting between them is exactly what it does not know about.
Frequently asked
How long does a value stream map take?
One product family, walked and drawn honestly, is a day or two for a small plant. Trying to map everything at once is the usual mistake and produces a wall chart nobody acts on.
Is it the same as a process flowchart?
No. A flowchart shows the sequence of operations. A value stream map adds the inventory between them, the time each stage takes, the information flow that triggers the work, and a lead time total at the bottom.