Value Stream Mapping
Value stream mapping is a lean-management method for analyzing the current state and designing a future state for the series of events that take a product or service from its beginning through to the customer. At Toyota, it is known as "material and information flow mapping". It can be applied to nearly any value chain.
Value Adding (VA): any activity that your external customers value, and would be willing to pay for.
Necessary Non-Value Adding (N NVA): any activity that is necessary but does not add value, for example any necessary support processes, legal regulatory requirements, etc.
Unnessary Non-Value Adding (U NVA): any activity that is unnessary, a.k.a. waste.
In order of importance.
Value Time (VT)
- The time spent on adding value. This is actually performing the work.
Process Time (PT)
A.k.a. touch time, work time, cycle time.
The time it takes to actually perform the work, if a person is able to work on it fully and focus on it fully.
Include task-specific doing, talking, thinking, etc.
Lead Time (LT)
A.k.a. throughput time, turnaround time, elapsed time.
The elapsed time from when the input to a step is available, until the step is compeleted i.e. the work is sent along to the next step.
Include Process Time, not just the waiting time.
Percentage Activity (%A)
- Calculate (PT / LT) * 100
Input Percentage Complete & Accurate (%C&A)
The percentage of inputs that are fully usable, i.e. that are complete and that are accurate, as measured by the person receiving the inputs.
Similar to "first pass yield" in manufacturing.
Rolled first pass yield (RFPY)
A.k.a. %Clean, %C&A for stream
Calculate %C&A * %C&A * %C&A ...
The percent of value stream output that goes through the process cleanly, i.e. without any need for rework.
Number of Handoffs (#HO)
Number of IT Systems (#IT)
Transportation (material, data, etc.)