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CISA Practice Question: During the implementation of a new ERP system,…
During the implementation of a new ERP system, the project team discovers that the legacy system data cannot be directly migrated due to incompatible data formats. The project manager proposes building a custom script to extract, transform, and load (ETL) data. Which of the following is the BEST course of action?
⚠ Common exam trap
Test-takers frequently assume custom scripts are inherently risky and choose to delay or abandon data, failing to recognize that with proper testing and validation, custom ETL is a standard and effective solution for incompatible data formats.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Proceed with the custom ETL script after thorough testing and validation.
Building a custom ETL script is a common and acceptable approach when legacy data formats are incompatible with a new ERP system. The key is that the script must undergo thorough testing and validation to ensure data integrity, completeness, and accuracy before migration. This balances the need for timely implementation with the risk of data corruption, which can be mitigated through rigorous quality assurance processes.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Manually re-enter all legacy data into the new system.
Why it's wrong here
Manual re-entry introduces transcription errors at scale and is impractical for the volumes typical of ERP migrations, undermining data integrity. It suits small static reference tables, not transactional history. The scenario needs a controlled, repeatable transformation process, which manual entry cannot provide.
- ✗
Delay the implementation until a commercial migration tool is available.
Why it's wrong here
Waiting indefinitely for a commercial tool stalls the project without guaranteeing format compatibility, and no vendor commitment exists. Delaying suits situations where a scheduled vendor release is contractually confirmed. The scenario calls for an immediate, controlled migration approach, which passive waiting does not satisfy.
- ✓
Proceed with the custom ETL script after thorough testing and validation.
Why this is correct
Custom ETL is the only viable route because the legacy formats are incompatible with direct migration. Proceeding after thorough testing and validation ensures transformed data is complete and accurate before loading, addressing the incompatibility while managing the risk inherent in bespoke extraction, transformation and load logic.
- ✗
Abandon the legacy data and start fresh in the new system.
Why it's wrong here
Discarding legacy data destroys historical financial and operational records needed for audit, reporting, and reconciliation, and provides no transformation path. Starting fresh suits greenfield deployments with no retained obligations. The scenario requires preserving data integrity through migration, which abandonment fails to deliver.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This CISA practice question is part of Courseiva's free ISACA certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the CISA exam.