Certified Information Systems Auditor (CISA) — Question 1042

A bank performed minor changes to the interest calculation computer program. Which of the following techniques would provide the STRONGEST evidence to determine whether the interest calculations are correct?

Answer options

• A. Review of the quality assurance (QA) test results
• B. Manual verification of a sample of the results
• C. Source code review
• D. Parallel simulation using audit software

Correct answer: D

Explanation

Parallel simulation using audit software allows for real-time comparison of the results generated by the modified program against a known standard, making it the most robust method for confirming accuracy. The other options, while useful, do not provide the same level of verification; QA test results may not cover all scenarios, manual checks are limited in scope, and source code reviews do not test the output directly.