Value Stream Map
The Value Stream Map (VSM) is a relatively simple, but extremely effective tool. It is one of the basic foundation tools of the Lean philosophy.
The VSM is a specialized process map. It identifies the process flow as well as the information flow. It also identifies critical metrics such as cycle times, inventory, yield, travel time, changeover time and others.
This allows you to view you to view your complete set of processes from a "high altitude" and very easily see where the roadblocks are. It helps you focus on improvement opportunities that will actually have an impact on the total business rather than focusing your time and efforts on improvements that may just impact one department or area.
One of the most important aspects of the map is the lead time line at the bottom of the map. This actually shows you how long the whole process takes and very easily shows where time is being "wasted" with non-value added activities.
A sample VSM is shown below. This is taken from Rother & Shook's "Learning to See". It was one of the first books to show in detail how to use this mapping tool. It is, even until today, considered to be the authority book on value stream mapping.
These maps use special Lean symbols which makes it very easy to "see" the whole business flow at one glance. Some of these symbols are shown below.
The typical way to use this tool is to first create a Current State Map. This map should reflect how the process is currently performing. All the metrics, flows, and steps should reflect how things are running as of today.
Once this is done, focus areas for improvement are known and activities such as root cause analysis and brainstorming are done to see how the waste in these areas can be eliminated or reduced.
A new map is then created with all the improvements incorporated into it. This is called the Future State Map. Actions are then implemented on the business processes to reflect the process in this new map.
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