What is the difference between a value stream map and a process flow diagram?

A process flow diagram shows the sequence of steps in a process. A value stream map goes further by including material and information flows, inventory levels, lead times, and key metrics at each step. It provides a holistic view of the entire value stream, not just the process steps.

Should I map the current state or future state first?

Always map the current state first. You need to understand where you are before you can plan where to go. The current state map reveals waste and bottlenecks that inform the future state design. Attempting to design a future state without understanding the current state leads to assumptions and missed opportunities.

How long does it take to create a value stream map?

A current state map for a focused product family can typically be completed in 1-3 days of dedicated effort. This includes walking the process, collecting data, and drawing the map. The future state design usually takes an additional 1-2 days of team discussion.

What are the most common symbols used in VSM?

Common VSM symbols include: process box (operation step), triangle (inventory), truck (shipment), arrow (push or pull flow), zigzag arrow (electronic information), lightning bolt (kaizen burst for improvement opportunity), and the timeline at the bottom showing lead time vs. processing time.

What is Value Stream Mapping (VSM)? | Definition, Steps & Examples

Value Stream Mapping (VSM) is a lean management tool that visualizes the entire flow of materials and information required to bring a product from order to delivery. A value stream map shows every step in the process — both value-added and non-value-added — along with key metrics like cycle time, lead time, changeover time, and inventory levels. It reveals where waste exists and guides improvement priorities.

How to Create

To create a value stream map: (1) Select the product family to analyze. (2) Walk the actual process from end to end (door-to-door). (3) Map the current state: draw each process step, inventory points, information flows, and transport. (4) Record key data at each step: cycle time, changeover time, uptime, batch size, number of operators. (5) Calculate lead time (total time through the system) and processing time (value-added time only). (6) Identify waste and improvement opportunities. (7) Design the future state map with proposed improvements. (8) Create an implementation plan. Accurate cycle time data from video analysis tools like Yamazo VAS strengthens the data quality of your VSM.

Example

A VSM of a bracket manufacturing process reveals: total lead time is 23 days, but total processing time is only 185 seconds. This means less than 0.01% of the total time is value-added. The map shows 15 days of raw material inventory, 6 days of WIP between stations, and 2 days of finished goods. The future state map targets reducing inventory to 3 days total, implementing flow between welding and assembly, and cutting lead time to 5 days.

What is Value Stream Mapping (VSM)? | Definition, Steps & Examples

How to Create

Example

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