7.4 Implementation

When transitioning from an old system to a new system, organizations must carefully choose an appropriate changeover method. The choice of implementation method depends on factors such as:

• Risk tolerance of the organization
• Available budget for implementation
• Time constraints for the changeover
• Size and complexity of the system
• Critical nature of the system being replaced

Each method offers a different balance of risk, cost, and speed of implementation.

Direct changeover is a method where the old system is stopped overnight and the new system is introduced immediately. This is often referred to as the "big bang" approach.

Direct changeover is suitable when:

• The new system has been thoroughly tested
• The organization can tolerate some risk
• Immediate benefits are required
• The system is not mission-critical or has adequate backup procedures

• Benefits are immediate – the organization can start using the new system right away
• Costs are reduced – since only one system is used, there is no need to pay for two sets of staff
• Less likelihood of a malfunction – since the new system will have been fully tested before implementation

• This method can be disastrous if the new system fails – there is no backup system to fall back on
• High risk – any problems with the new system immediately affect the entire organization
• No safety net – if errors occur, they affect all users simultaneously

Parallel running is a method where the old and new systems are run side by side for a time before the new system takes over altogether. During this period, both systems process the same data, and outputs are compared.

Parallel running is suitable when:

• The system is mission-critical
• The organization has a low risk tolerance
• Staff training is needed
• Data accuracy must be verified before full changeover

• If the new system fails, the old system is still available as a back-up – this provides maximum safety
• Possible to train staff gradually – staff can learn the new system while still having the old system available
• Staff have time to get used to the new system – reduces stress and allows for a smoother transition
• Outputs can be compared – ensures the new system is working correctly

• More expensive than direct changeover – since extra staff are needed to run both systems together
• Increased workload – staff must maintain and operate two systems simultaneously
• Time-consuming – the parallel period extends the overall implementation time
• Resource intensive – requires double the hardware, software, and personnel resources