Value stream mapping, from product family to implementation plan

What a value stream map is

A value stream is every action, value-adding or not, needed to take one product family from raw material to the customer's hands. A value stream map (VSM) is a one-page, hand-drawn-style picture of that stream showing two things at once:

• Material flow — what physically happens to the product, left to right along the bottom: suppliers, processes, the inventory between them, shipping.
• Information flow — how each process knows what to make next, along the top: orders, forecasts, schedules, kanban.

Underneath sits a timeline that compares how long a part waits (days) with how long it is actually worked on (seconds). That gap is usually the most striking thing on the page.

The method grew out of Toyota's "material and information flow diagrams" and was made widely known by Mike Rother and John Shook's workbook Learning to See (Lean Enterprise Institute, 1999).

Why and when to use it

Good times to map: lead times are long or unpredictable, there is a lot of WIP, you are launching a lean program, laying out a new line, or customers are complaining about delivery.

Not the right tool: for a problem inside one process (use problem solving / A3), or for a one-off job shop flow with no repeating product family (use a process flow chart or spaghetti diagram instead).

The four steps

1. Pick a product family. One map per family of products that pass through similar downstream steps.
2. Draw the current state. Walk the actual flow, collect the data yourself, and draw what really happens today.
3. Design the future state. Use lean principles to draw a leaner flow you can achieve in roughly 3–12 months.
4. Write the implementation plan. Break the future state into loops, set goals and owners, and review on a schedule.

Current and future state are drawn almost together — insights about the future appear while you map the present. Assign one value stream manager who owns the whole flow and reports to the top of the site.

Step 1 · Choose a product family

Customers care about specific products, not your whole plant. Mapping everything at once is unreadable. Build a product-family matrix: products down the side, process steps across the top, and mark which steps each product uses. Products that share most downstream steps (closest to the customer) form a family.

Then write down the family's customer demand: units per month, the mix, how often it ships, and how it's packed.

Before you walk the floor

A first pass takes half a day to a day for a single plant. How you walk matters more than how fast.

1. Walk the whole stream quickly first, door to door, to get the sense of flow and sequence.
2. Then start at shipping and walk upstream. You begin with what the customer pulls and see each step in relation to it.
3. Collect the data yourself. Use a stopwatch and count inventory on the floor. Don't rely on standard times or system quantities — they're often wrong.
4. Map the whole stream yourself, even with a team. Splitting it into pieces means no one sees the whole.
5. Draw by hand in pencil first, on the floor, on A3 paper. Then capture it here when you're back at a desk.

Data to collect

Print a blank collection sheet from the Data sheet section, or take the gemba walk on your phone.

Symbol library

All of these are in the builder's palette. Drag them onto the canvas.

See every symbol on its own page, with when to use each →

Flows (arrows)

Step 2 · Draw the current state

Drawing in this order keeps the map readable and mirrors how you walked it:

1. Customer in the top-right corner, with a data box of demand.
2. Production control in the top-middle; the supplier in the top-left.
3. Process boxes left to right along the bottom, in flow order. A new box starts wherever flow stops.
4. Data boxes under each process: C/T, C/O, uptime, operators, shifts, scrap, EPEI.
5. Inventory triangles between processes with counted quantities (and days).
6. Material flow: push arrows between processes; shipment arrows and trucks from supplier and to customer.
7. Information flow: electronic and manual arrows from customer → production control → supplier and → each process, labeled with what is sent and how often.
8. Timeline along the bottom: days of inventory on the top steps, processing seconds on the bottom steps, totals at the right. The builder draws this for you.

Key calculations

Available time

Takt time — the pace the customer sets

A process with C/T above takt can't keep up without overtime or another resource. Well below takt usually means it batches and overproduces.

Inventory in days

Lead time, processing time, PCE

PCE for a traditional batch flow is commonly well below 1%. The builder converts lead-time days to seconds using your working time per day; some teams use 24-hour calendar days instead, which gives an even lower number. Pick one convention and keep it.

For a line with step times, the takt time calculator checks every step against takt.

Operators needed

Other useful measures

• Uptime = actual run time ÷ available time.
• EPEI (every part every interval) — how long it takes to run every part variant once; driven by changeover time and the time left over after running demand.
• Pitch = takt time × pack-out quantity — the time increment you release and take away work in at the pacemaker.
• Rolled %C&A = product of every step's %C&A — the share of work that gets through with no rework (office maps).

Step 3 · Design the future state

Aim for each process to make only what the next process needs, when it needs it, linked by either continuous flow or pull. Work through these questions, roughly in order, and draw the answers:

1. What is the takt time? Based on available working time of the downstream processes closest to the customer.
2. Build to a finished-goods supermarket, or straight to shipping? Depends on customer buying behavior, reliability and product variety.
3. Where can you use continuous flow? Combine steps into a cell where parts move one at a time.
4. Where do you need supermarket pull? Where flow is impossible — shared equipment, long changeovers, distant suppliers. Use FIFO lanes where a supermarket isn't practical.
5. Which single point gets the schedule? This is the pacemaker. Everything downstream of it flows; everything upstream is pulled.
6. How will you level the mix at the pacemaker? Spread products evenly over time instead of big batches of one.
7. What increment of work will you release? Release and take away a consistent amount (pitch) to set a steady rhythm.
8. What improvements are needed? Changeover, uptime, quality, cell layout — mark each with a kaizen burst.

Open your current-state map and use New map → Copy this map as future state, then redraw it with supermarkets, FIFO lanes, the pacemaker and kaizen bursts.

Step 4 · The implementation plan

Split the future-state map into loops:

• Pacemaker loop — the pacemaker process and everything downstream to the customer. Usually implemented first because it sets the pace for the rest.
• Additional loops — each pull loop upstream, between supermarkets.

For each loop, write: the objective and measurable goal, the kaizen events needed, an owner, dates, and how you'll check results. Put it on a one-page value stream plan and review it monthly. Typical order: stabilize the pacemaker loop → build continuous flow → install pull → level the schedule → extend upstream to suppliers.

Office and service value streams

The same idea works for quoting, order entry, engineering changes, claims, hiring. Differences:

• Use process time (PT) and lead time (LT) per step, and %C&A (percent complete and accurate) to capture rework.
• "Inventory" is work in queues: emails, files, tickets, approvals waiting.
• Map the systems and hand-offs; information flow and material flow often merge.

In the builder, enter %C&A on each process box and the rolled %C&A appears in the summary.

Common mistakes

Glossary

Value-added (VA)

Work that changes the product in a way the customer will pay for.

Cycle time (C/T)

How often a part is completed by a process, as timed by observation.

Changeover (C/O)

Time to switch from the last good part of one product to the first good part of the next.

Uptime

Share of available time the equipment actually runs.

Takt time

Available working time divided by customer demand; the rate the customer needs.

Lead time

Time for one part to move all the way through, start to finish.

PCE

Process cycle efficiency: value-added time ÷ lead time.

EPEI

Every part every interval: how often each variant can be produced.

Pacemaker

The one process that receives the customer schedule and sets the pace.

Supermarket

A controlled store of parts from which the downstream process withdraws.

FIFO lane

First-in-first-out queue with a max quantity between two processes.

Kanban

A signal (card, bin, electronic) that authorizes making or moving parts.

Heijunka

Leveling the type and quantity of production over time.

Pitch

Takt × pack quantity; the increment of work released to the pacemaker.

Push

Producing to a schedule regardless of whether the next step needs it.

Pull

Producing only to replace what the downstream step has used.

Kaizen

Continuous improvement; on a map, an improvement needed to reach the future state.

%C&A

Percent complete and accurate: share of output the next step can use without rework.

Printable data collection sheet

Take this to the floor with a clipboard and stopwatch. One row per process, in flow order, starting at shipping.

Print the data sheet

Further reading

• Mike Rother & John Shook — Learning to See (Lean Enterprise Institute). The original VSM workbook.
• Dan Jones & Jim Womack — Seeing the Whole Value Stream. Extended maps across companies.
• Mike Rother & Rick Harris — Creating Continuous Flow. Designing cells.
• Rick Harris, Chris Harris & Earl Wilson — Making Materials Flow. Supermarkets and material handling.
• Karen Martin & Mike Osterling — Value Stream Mapping. Office and service value streams.
• Lean Enterprise Institute — lean.org.