Value Stream Mapping
VSM maps the entire value stream for one product family — processes, inventories, information flow and time — on a single map, so waste and bottlenecks become visible and can be prioritised.
One bounded product family is chosen (one map per family — never “the whole factory”)
The people who work in the process can take part — not just their managers
Real data is available or can be measured on the day: cycle times, inventory levels, changeover times
Start at shipping and walk the value stream backwards to raw materials. Backwards, because you see the flow through the customer’s eyes and aren’t coloured by “the usual order of things”. Note every process step, every inventory point and every transport along the way — on the floor, not from memory.
For each step, record: cycle time, changeover time, uptime/reliability, number of operators and batch size. At each inventory point, count the actual stock — a physical count, not the system number. Convert stock to days: stock ÷ daily customer demand.
Map how each process step knows what to produce: orders, plans, forecasts, shouts. The information flow is drawn at the top of the map — it often reveals that several steps are planned independently of one another, which is a main cause of the buffers.
At the bottom of the map, draw the timeline: value-adding process time vs. total lead time (incl. all inventory and waiting time). The ratio between the two is the flow efficiency — typically under 5%, and that number is the map’s most important message to management.
With the current state on the wall, ask the standard questions: where can flow be created? Where should pull/kanban be used instead of forecasting? Which single point should be scheduled (the pacemaker)? What is the takt time? The future map is a design, not a wish list — each element must be justifiable.
The difference between the two maps is broken down into bounded efforts (typically 5-10), each with an owner, a target and a deadline. The plan is reviewed monthly by management — a VSM map without a follow-up cadence is wall decoration within a quarter.
How it goes wrong in practice — and this is where most implementations part ways.
A VSM drawn from memory shows the process you think you have. The decisive findings — detours, hidden buffers, duplicated work — are only found by physically walking the flow.
A map of everything shows nothing. One product family at a time — choose the most important or most painful first.
The ERP system’s cycle times and stock numbers almost always differ from reality. The standard requires measured numbers — the gap between system and reality is itself a finding.
Half of all VSM efforts stop after the first map. The current state is the diagnosis; without a future map and plan, you have spent a day documenting problems you already sensed.
The method only works when it becomes daily routines and leadership behaviour. The operations check shows in 4 minutes where your operations stand — and what should come first.