Value Stream Mapping – Common Mistakes
During many first time Value Stream Mapping exercises, we have noticed some common mistakes. Many times when the mistake is made, it is not recognized and the Value Stream Mapping tool is called into question. It’s like trying to use excel as a word processor, it kind of works but you just don’t quite get the results you were expecting. So here are some of our observations.
1. You start to follow the people doing the work. We all start out understanding that we are doing Value Stream Mapping on a product or service however at some point, the person doing the job leaves the product and does something else. Rather than staying with the product we start to follow the person. It may even seem like we should follow the person as the task they are doing is related to the product we are following.
For example in a dentist’s office, the product we will follow is the patient. The patient comes in, they register, they sit down and they wait. They get called into the office and the dentist performs the work, they leave. The nurse takes their folder and does some work to it, she then works on the computer to update the file and finally, she puts the file away.
In this case we have stopped following the patient and we have started to observe the work being performed by the nurse.
2. Trying to do a final Value Stream Map without the product or service actually being performed. We all know that it is sometimes difficult when you are training people to do Value Stream Mapping to always ‘see’ the product move through the entire process. It is sometimes necessary to leave the client with homework to actually observe the process and fill in all the boxes.
There are cases however where companies think that there is not enough time to get a complete Value Stream Map, the process is too long or won’t be running for another month and they need to present to management a savings plan by the end of the week. They frequently think that they can go to their engineered standards and fill in the information boxes and then predict their savings.
In this case the person has forgotten some of the basis of Lean. First without observing the inventory, they don’t have a Value Stream Map, they have a Process Map. Second without observing how the time standards were arrived at, how will you determine waste opportunities. Third the person doing the work may have many distractions – for example it may take me an hour to change the brakes on a car but every time I start, I have to do 3 oil changes. We need to observe the work and more importantly what’s happening to our product when the work isn’t being done.