DISCUSS ANY FOUR APPROACHES TO SYSTEM
CHANGEOVER.BRIEFLY OUTLINE THE ADVANTAGES
AND DISADVANTAGES
SYSTEM CHANGEOVER IS THE PROCESS
O F P U T T I N G N E W I N F O R M AT I O N
SYSTEM ONLINE AND RETIRING THE
O L D S Y S T E M , F O R I N S TA N C E ,
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 backup.
 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 subsystem
 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
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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.