Parallel running refers to the practice of two business systems — usually an older system and its newer replacement — working side by the side at the same task during a period of changeover. This period of time assures that the new system is working properly by allowing for comparison to the results of the old system. Once the new method of doing things is proven effective, the old method can be jettisoned and the period of parallel running is complete. The phrase parallel running can refer to the process of switching a portion of a business's information technology operations to a new system, or to the technique favored by human resources departments in which prior staff stay on board during the transition to a new staff.
Any time a change is implemented in the business world, there is naturally some uncertainty about how the new facets of the operation will perform in relation to the old ones. Since this is the case, business leaders look for ways to combat this uncertainty and ensure that things keep running smoothly even during periods of operational transition. One way to do this is the technique of parallel running, which allows the old and the new to work side by side at the same task during a transitional period.
By instituting parallel running, a business can make sure that their new initiative allows operations to run smoothly in the short-term. This technique is not as concerned with the long-term effects of the change. It is just a way to make sure there is not any interruption in business flow as new methods replace old ones. With a gradual transition and the new implementation working alongside the old standard, all doubts about the feasibility of the change can be assuaged.
As an example of parallel running, imagine a firm that, due to an ownership change, wants to bring in its own staff to run things. Making this change all at once can be problematic if the new staff doesn't know all of the daily basics of the operation. For that reason, the new regime may keep the old staff on board for a period of time to do their normal jobs, while the new staff shadows them and gets the on-hands experience they need. Once the results of the new staff match the results of the old staff in terms of productivity and necessary operational duties, the old staff can be let go.
Many businesses often use the theory of parallel running as a way to make sure that new computer software is capable of handling the tasks required of it. The old software and the new software receive the same input from the business. After some time has passed, the outputs from the two software programs can be compared to make sure that a proper transition can be made without sacrificing functionality, efficiency, or productivity.