In what scenario is "parallel running" most beneficial?

Parallel running is particularly beneficial in scenarios where data integrity is critical during transitions. This method involves running the new system alongside the old system for a certain period, allowing both systems to operate concurrently. This dual operation ensures that any discrepancies or issues can be identified, allowing for immediate corrective actions.

By comparing outputs from both systems, organizations can verify that the new system is functioning correctly and that data is being processed accurately. This is especially important when the stakes are high, such as in financial or healthcare settings, where incorrect data handling could lead to significant consequences.

In contrast, running a legacy system that is unsupported or transitioning to a new system without adequately testing independent components may not provide the same level of assurance about data integrity. Immediate results may also not be possible without sacrificing thorough testing, which can lead to potential errors going undetected. Hence, the priority of maintaining and verifying data integrity firmly supports the choice of parallel running in such cases.