Which conversion method implements aspects of the new system progressively until it replaces the old system entirely?

The correct choice for the method that implements aspects of the new system progressively until it fully replaces the old system is phased conversion. This approach allows for the gradual integration of the new system, enabling specific modules or features to be deployed and tested in manageable parts. As each phase is completed successfully, it builds on the previous one, ensuring that the overall transition can be monitored and adjusted as needed.

Phased conversion minimizes the risk associated with a full-scale implementation all at once, which can be overwhelming and detrimental if issues arise. By allowing parts of the new system to be adopted step by step, organizations can better manage user training, assess operational impacts, and ensure system stability before moving on to the next phase.

This method is particularly effective for large or complex systems where a complete switch-over could lead to significant disruptions. Gradually moving through phases helps teams identify problems and resolve them without impacting the entire system at once.