System conversion strategies: which method runs the old and the new system simultaneously so users continue using the familiar system during transition?

Introduction / Context:
When replacing an information system, organizations choose a conversion strategy balancing risk, cost, and speed. Common approaches include direct cutover, phased conversion, pilot conversion, and parallel run. Understanding the operational implications of each strategy helps managers plan staffing, data reconciliation, and risk mitigation during go-live periods.

Given Data / Assumptions:

• The question seeks the method where the old and new systems are used at the same time.
• Users continue to operate the old system while the new system processes the same transactions.
• The goal is to compare outputs and ensure stability before retiring the legacy system.

Concept / Approach:
Parallel run operates both systems concurrently for a defined period. Transactions are entered into both, and results are compared. Discrepancies prompt investigation and correction until confidence is achieved. While costly in labor and potentially duplicative, parallel running reduces risk because the legacy system remains a fallback if the new system fails to meet requirements. By contrast, “multiprocessing” and “multitasking” are technical execution modes on a computer, not conversion strategies.

Step-by-Step Solution:

Verification / Alternative check:
Project management and SDLC references list parallel run as a standard conversion option alongside pilot, phased, and direct cutover, confirming terminology and practice.

Why Other Options Are Wrong:

• Multiprocessing: multiple CPUs or cores executing tasks; not a deployment strategy.
• Multitasking: time-sharing multiple tasks on one system; not a conversion approach.
• All/None: not applicable because a specific named method exists.

Common Pitfalls:
Underestimating the effort to maintain data consistency across both systems during parallel periods; plan reconciliation procedures and clear cutover criteria.

Final Answer:
Parallel run