I am often asked about the difference between value stream maps and process maps. Which is better? Which one should I use? Your project may benefit from either or both tools. So, let’s look at each of them and their benefits to your next project.
Process Mapping
Let’s begin with the tool most of us are familiar with. Process Mapping is a graphical tool that thoroughly investigates a process and identifies all the activities that occur within it. It includes things such as start points, endpoints, decision points, directional arrows, and swim lanes so that we can visually see how a process flows and who is performing the activities.
Once the map is validated, we look at the sequence of activities. We may be able to see inefficiencies within the process and identify activities that are not needed or activities that could be reordered for better efficiency. With the defined process map, we can measure the time needed to complete each activity so that we can apply lean process analysis and further reduce the waste within the process.
We also use process mapping in the improve phase where we define the new to-be process and test and verify that the desired improvements can be achieved. Process maps can also be used in the control phase as a tool for training process owners on new processes they need to adopt.
Value Stream Mapping
Developing a detailed process can require several resources and be time intensive, you must go to the process to observe and document the activities to ensure that you are accurately capturing it. If you are early on in your project and you are not sure where in the process you need to aim your focus, you may feel it is too large in scope to justify creating a detailed process map. A value stream map may help.
Value stream mapping was originally used in the auto industry in Toyota’s lean manufacturing process. Like process mapping, it is a tool used for streamlining work processes. However, value stream mapping takes a higher-level look at the process. It focuses on understanding the flow of the goods or services, from purchase to delivery. It usually contains seven to ten high-level activities.
A value stream map can be extremely detailed as well. It can include key lean metrics such as cycle times, defect rates, wait times, headcount, inventory levels, and changeover times, depending on your project. It can be a valuable diagnostic tool for identifying the high-level activities within the process where the greatest need for improvement is.
For example, the value stream map includes the cycle times or the time it takes to complete each of the seven to ten activities as well as the waiting time that lapses between these activities. For this reason, a value stream map is a great tool for identifying where waste is occurring, within and between processes. Once the area(s) you want to focus on is identified, you can drill down using a process map to capture all the activities, find the true bottleneck, and address it.
As is the case with process maps, value stream maps can also be used for the new to-be process as your project reaches the improve phase.
Value stream mapping can also be beneficial for organizations when identifying projects. It helps companies avoid randomly making improvements by allowing them to identify and prioritize areas of improvement upfront. It also aids them in setting measurable goals for the projects.
These mapping tools can be beneficial with many methodologies including; Lean Six Sigma, Lean, Kaizen and Design for Six Sigma.
Keep in mind that both tools take an investment of time, so it is important to properly scope your project and define your process boundaries before mapping your process. For help with scoping your project, consider using a SIPOC.
