Value stream mapping (VSM) was introduced at Toyota as a method for investigating production and design flows. The approach focused upon the manner in which materials and information flowed throughout a process to eventually yield value to an end customer. Its goal was to help managers identify and eliminate waste. In doing so, they could reduce the costs of production and lead times while improving customer satisfaction.

Originally, the methodology was used exclusively in lean manufacturing environments. Today, the discipline is implemented within organizations in a variety of industries. This article will assume the reader has a basic understanding of the system through which value stream mapping is implemented. Instead, we'll explore three potential hazards associated with its implementation.

#1 - Lack Of A Repeating System

VSM uses maps to follow resources through an iterative design. That is, there must be an identifiable process that repeats in order that the VS map can accurately determine controls. It is through that determination that sources of waste are isolated.

Many organizations apply VS mapping to business processes which fail to meet that standard. In some cases, the inputs vary along the way and as a result, identifying a repeating control is impossible. If a control cannot be identified, a Future State cannot be proposed with a reasonable level of expectation.

#2 - Following Human Inputs

One of the most common mistakes made when performing value stream mapping is that the observer will mistakenly follow human inputs rather than the control. For example, consider your local coffee shop and suppose the process under study is the creation of a latte. A customer enters the shop and orders the latte, thereby starting the observation. The study concludes once the latte is delivered to the customer. However, an observer may continue following the preparer as he or she cleans the espresso machine.

Doing so damages the accuracy of the VS map and therefore, prevents the proposal of an accurate Future State.

#3 - VS Mapping Without Observation

More than ever, companies maintain detailed records on computer regarding every process on which they rely. For example, a manufacturing plant might have records detailing the amount of time required to transport, package, or unpack items within a warehouse. The danger here is that the observer may be tempted to construct a VS map from these records rather than actually taking the time to observe the process. In many cases, the recorded details may fail to take every factor into account.

For example, a manufacturing plant might maintain that a warehouse employee can transport an item from the delivery section of the facility to the packaging area in 4 minutes. A VSM observer might rely upon that metric rather than visiting the warehouse to watch the transaction occur. In reality, due to phone calls and sporadic stops, the employee may actually require 17 minutes to transport the item. Unless observed, that waste would not be identified.

Accuracy Follows Proper Implementation

Value stream mapping is an effective methodology for uncovering waste in production and design flows. But, like other methodologies (i.e. Six Sigma, BPM, etc.), it must be implemented carefully. Controls must be properly identified and followed. Observers must be able to accurately determine when an observation ends (rather than continuing to follow human inputs). And of course, VS mapping requires actual observation of processes rather than a reliance on recorded "standards." If these rules are not followed, an accurate Future State map that addresses existing waste cannot be proposed.