In monitoring process performance, we often focus on throughput—measures such as how many service orders a technician can complete in a day, or how many widgets are produced every hour. These measurements look at one aspect of productivity, which is how well a machine or an individual is doing the work.
Often we overlook the elapse time which is time between tasks. The elapse time is idle time during which no one is doing any work. It is important to monitor that and beware of how significant it is.
The idle time could be attributable to a gap in communication. For example, the next worker in line is not aware that there is work waiting for him. Idle time can be caused by incomplete information resulting in the work being held up.
Long elapse time is prevalent particularly with work that spans across different teams. It could add up to significant delays and easily erodes the efficiency gains you have achieved from performing the isolated. So pay attention to that when you monitor process performance.