This is a traditional flowchart for a manufacturing process. Complaints directed at this process mapping tool include that it is limited in what data it can represent while also being difficult to understand. Source: Mark A. Nash
Process mapping tools are found in every quality practitioner’s toolbox. Whether flowcharts, SIPOCs (suppliers, inputs, process, outputs, customers), mind maps or swim lanes, there is a process mapping tool that can document the process under review. Since the 1970s, when the quality movement took hold in the United States, the most often used and most widely accepted of these tools has been the flowchart. It is from this basic mapping concept that all others have emerged.
For decades flowcharting has been the tool of choice. And why not? When documenting a process and sharing the information with others, flowcharting provides an immediate understanding of the basic tenets behind its methodology. It is a part of the shared language enjoyed by technical experts dealing with simple and complex processes alike.
Continuous Improvement Today
Flowcharting, however, has lost credibility and momentum in recent years as continuous improvement has evolved from being managed and controlled by a few experts to being a part of all employees’ jobs on an ongoing basis. While flowcharting does an excellent job at capturing the logical flow of a process, it has two fundamental limitations: 1) a single flowchart typically only captures the flow of the product or service or captures the flow of the communication-but not both; and 2) many nontechnical employees, including many managers, struggle to interpret this 2-D representation of the process.
As nonexperts attempt to understand flowcharts, they may look for errors in the process map that make it incorrect. Believing they have proved the map flawed, they may put the document aside and focus on data they do understand. Ultimately, this causes frustration for all team members working on quality issues.
The challenge then becomes how to both ensure accuracy and explain these maps in such a way that all employees can understand them. This is both a challenge and a curse. It may take days or weeks to get the flowchart 100% accurate. Likewise, it may take hours to explain the map to the degree that the entire audience understands what is being presented.
And yet, at the end of the day, only the logical flow of product or service is presented. The only way to bring in additional information is through adding tables and charts as addendums. Any progress or momentum made often times is lost when a new round of explanation is required to tie it all together.
This is a value stream map (VSM) for a manufacturing process. Compared to a traditional flowchart, the VSM makes it easier to see the flow of the process from left to right on the page. It also includes information not shown in a traditional flowchart. Source: Mark A. Nash
A Better Alternative
With the introduction of the Toyota Production System to the United States came a process mapping concept now called value stream mapping (VSM). Popularized by the book “Learning to See,” by Mike Rother and John Shook, VSM has overtaken all other forms of processing mapping used by companies practicing lean manufacturing/lean enterprise.
The power behind VSM is in both the simplicity of the map and the amount of information that can be included in a single document. Both process flow and communication are included. The people working within the process are shown at the point where they are working when the map was created. Inventory is shown where it exists. By using the quantity of the inventory, shown in comparison to the cycle times for each process step, it is easy to compare total cycle time to process lead time.
Additionally, travel distances, defect rates, changeover times and other essential information all can be captured on a single map. But perhaps the strongest argument for using VSM as a process mapping tool is how easy the maps are to explain to an audience. By abandoning the logical paths of the process for the visual and actual order of the flow, VSM can be explained to and comprehended by most people through a short presentation.
The altitude at which one chooses to draw a map is no different than any other process mapping technique. The power, however, lies in the additional data that is incorporated into the map.
Process Mapping Tomorrow
Value stream mapping is a relatively new methodology in comparison to traditional flowcharting. New concepts, ideas and uses are introduced all the time. What started out as a tool to document process and communication flow on the manufacturing floor in lean environments in 1999 has become-in 10 short years-a powerful mapping methodology used throughout the business world. Many Six Sigma practitioners have adopted this tool, and in the years to come, VSM may very well become the default tool, or at least the initial tool of choice, for process mapping worldwide.