Systems Life Cycle: Implementation

Methods Direct changeover Parallel running Phased implementation Pilot running

Direct changeover Switch off the old system and switch on the new. Simplest scenario Old systems switched off, new system takes over completely Non critical systems only the new system replaces the old system in one go saves money in wages/very fast method of implementation BUT if anything goes wrong you don’t have the old system to fall back on Cannot go back to old system if any problems

Parallel running Both old and new systems run side by side till new system is working properly Necessary in critical situations If the new system breaks down you still have the old system as a backup BUT It can be a slow process/all tasks have to be performed twice Expensive in terms of resources (may need two sets of staff)

Phased implementation New system is brought in one section at a time Can ensure each part of new system works properly before changing the next part Eg new library system BUT Takes longer than direct changeover If new system unsuccessful, may lose some data

Pilot running Eg in large banks or corporations One branch changes to new system, identifies any problems Other branches function as normal Problems can be identified & solved before new system is rolled out to all branches BUT If new system unsuccessful, may lose some data

Summary Direct changeover The old system is scrapped and immediately replaced by the new system. With this option there is a danger that there may still be problems with the new system. Even though it is the most risky type of changeover, many companies use this method. Phased changeover The change over is split into phases or stages. Each stage is introduced one at a time and the old system is kept running to do the remainder of the tasks that have not yet been changed.

Summary (continued) Parallel running Running both the old and new system until you are certain the new system is working correctly. Parallel running is likely to be the most expensive as it involves doing the work twice for a period of time. However, it is the safest. If there are any bugs in the new system, you can always go back to the old system while the problems are corrected. Pilot changeover Changing over in a small part of the company to start with. Only when the system is deemed satisfactory will it be rolled out to the rest of the organisation. A supermarket introducing a new 'self-scanning' system might choose to introduce it in two or three stores at first. This is a pilot changeover.