Value Stream Mapping is a mapping method that draws the entire value stream — processes, inventories, information flow and time spent — on a single map, so waste and bottlenecks become visible. The result is a current-state map, a future-state map and an action plan.
VSM differs from ordinary process diagrams by including time (process time vs. lead time) and information flow. The typical finding: process time makes up less than 5% of lead time — the rest is waiting and inventory.
A VSM analysis can be completed in a day for one product family, if the right people are in the room: those who actually work in the process, not just those who drew it.