DISCUSS ANY FOUR APPROACHES TO SYSTEM CHANGEOVER DISCUSS ANY FOUR APPROACHES TO SYSTEM CHANGEOVER.BRIEFLY OUTLINE THE ADVANTAGES AND DISADVANTAGES System changeover is the process of putting new information system online and retiring the old system, for instance, changing from a manual system to a computerised system

Direct change over/ Cold Turkey Cutover This is an approach where the old system is cut and overwritten by the new system, that is, the old system is stopped and the new system starts simultaneously and it becomes operational. It may be the only approach to take when two systems cannot co-exist or activating the new system is an emergency. An example can be the immediate switch from electricity to an automatic generator when there is a blackout in places like hospitals.

Advantages Less expensive and easy method as only one system is in use, unlike other approaches like the parallel approach. Has a short conversion time since the organisation immediately switches from the old system to the new system. There is no need for any interfaces between the old and the new system.

Disadvantages High risk of loss of data as a firm cannot revert to the old system as a backup plan. It involves more risk of total system failure as system errors that are not detected during the walk through and testing steps may materialise unexpectedly, which may disrupt the system. It also opens risk for the system not to be accepted by its users.

PARALLEL OPERATION The word parallel suggests things that are being run simultaneously It requires that both the old and new systems operate fully for a specified period of time When users, management and the information technology group are satisfied that the new system operates effectively and efficiently, the old system is then terminated.

ADVANTAGES Low risk is involved , if the new system does not work correctly the old system can be used as a back-up. By running two systems the user can reconcile outputs to identify debug errors before switching to the full operation of the new system. The old system can be used as back-up. Also, gives room to reversing the decision if the system fails to meet organisation objectives.

DISADVANTAGES It is costly as it essentially doubles resource consumption and data has to be input in both systems Users must work in both systems and it results in increased work load which can lead to overtime costs and processing delays. Increases or makes room for more errors as employees are expected to process all transactions twice.

PILOT OPERATION The method involves the implementation of the new system at a selected location/department/division within the organisation. It is mainly used by large organisations that have multiple locations or largely independent departments. The division or department that uses the system first is called the Pilot Site. The old system continues to operate within the entire organisation including the pilot site and if the system proves to be successful at the pilot site, it is implemented to the rest of the organisation.

ADVANTAGES Any implementation problems affect the pilot site only and not the whole organisations’ system, therefore any problems encountered can be rectified quickly, reducing system failure. It is less expensive as compared to parallel operation because pilot site only uses both the old and new system for a limited period of time. It can be designed or adjusted before putting it to the entire organisation. It is easier to monitor as focus is given to only one department.

DISADVANTAGES If the system that is implemented is successful in one department, it does not guarantee the success of the system in every department within the organisation as every department has its needs. Has a long conversion time There is a need for interfaces between old and new systems.

PHASE-IN OPERATION It is the implementation of the new system in modules or stages of phased operations for example one might implement the new system by starting with the sales sub-system followed by the inventory control subsystem and finally the purchases sub-system Implementing special conversion system that provide temporary interfaces during the change-over period can assist in the phase-in.

ADVANTAGES By phasing in the new system in modules, the risk of a system failure is reduced as the risk of errors or failures is limited to the implemented module only. It is less expensive than the full parallel operation method.

Disadvantages It can create incompatibilities between new subsystems and yet to be replaced subsystems. It limits the extent of implementation problem but may not be possible with other subsystems. It can be costly where the system involves a large number of separate phases.

The need for post implementation review; It can produce insight into ways to improve the process for the future system. To see if the system has achieved the organisation`s objective. To increase the efficiency of the system by correcting any errors in the implementation system. To measure the performance of the system against expectations . To add something new, if it is an in-house package. To check if the system is operating at full capacity. Improves the ability of analysts to evaluate costs and benefits. The knowledge of the review being performed motivates the members of the project design team. It helps in evaluating internal controls in the new system.

b) Why is post implementation review necessary for a new system?(8) A post implementation review`s objective is to measure the success of the system and processes. system designers and analysts strive to produce a system that is on time, on budget and meets user needs but it is not always possible.