Which systems conversion technique removes the old system entirely and activates the new system immediately in its place?

Introduction / Context:
When implementing a new information system, teams must choose a conversion strategy balancing risk, cost, and speed. One aggressive option is to retire the old system completely and switch users to the new one at a defined moment. This direct approach is commonly called crash conversion or direct cutover (often informally the big bang).

Given Data / Assumptions:

• A legacy system is being replaced by a new system.
• There is a specific go-live date and window.
• Rollback plans may be limited compared to safer strategies.

Concept / Approach:
Crash (direct) conversion involves shutting down the old system and making the new system live for all users at once. It reduces the overhead of dual running and speeds time to benefit but carries higher operational risk if defects surface post-cutover. It is chosen when parallel operation is impractical, when interfaces force a single switchover, or when business imperatives demand immediate change.

Step-by-Step Solution:

Verification / Alternative check:
Compare with alternatives: pilot converts a subset of users; phased converts functions or sites incrementally; parallel runs both systems together. Only crash conversion retires the old system immediately for everyone.

Why Other Options Are Wrong:

Common Pitfalls:
Inadequate data reconciliation, missing rollback criteria, and weak hypercare staffing increase risk with direct cutover.

Final Answer:
Crash (direct) conversion.