When looking at any existing process, people often have a hard time visualizing the enormous amount of delay, waste, and nonvalue-added work involved. That’s where a time value map comes in; it makes the invisible waste visible. A time value map shows value-added and nonvalue-added activities and delays.
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The 3–57 rule
Managers often say: “My people are busy.” But when you follow a work product through a process, you soon discover that people may only be working on it for three minutes out of every hour. The other 57 minutes are preventable delays. A time value map helps illustrate this problem.
Here is an example of a time value map. Any bar above the center line is value-added (VA). Any bar below the center line is nonvalue-added (NVA). The center line represents the timeline for the process, from start to finish. The gaps between bars are assumed to be no-value added delays (i.e., queue or wait times) and can be eliminated with value stream mapping and spaghetti diagramming. From a lean perspective, the goal is to eliminate the NVA and delays to accelerate the process.
Ideally, one would want the time value map to look more like the following with minimal wait time and NVA:
Although time value maps can be drawn by hand, that can take a lot of time. And they are almost impossible to create in Microsoft Excel. However, they are easy to create with the QI Macros Time Value Map Template.
To create a time value map in QI Macros for Excel:
1. Click on “Lean Tools->Time Value Map” to open the template.
Click for larger image.
2. Put the start time in E2.
3. Put the touch time (duration) for each activity, value-added or nonvalue-added, in column B.
4. Put the queue (i.e., wait) time in column C.
5. Put a “1” or “–1” in column D for value-added (1) or nonvalue added (–1).
6. Set the interval for the chart (e.g., 0:01 minutes or 0:05 minutes).
7. Click the Create Time Value Map button.
This will also give a column chart of VA vs. NVA vs. total elapsed time.
The column chart shows that value-added activities account for only about 7 percent of the total elapsed time. Eliminating delays between steps and nonvalue-added processing will dramatically improve performance and customer satisfaction.
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