In testing a computerized accounting system using the test data approach, which statement is true?

• A. Test data are processed by the client's computer programs under the auditor's control
• B. Several transactions of each type must be tested
• C. Test data must consist of all possible valid and invalid conditions
• D. The program tested is different from the program used throughout the year by the client

Answer: (A)

In the test data approach, you verify that the client’s system processes input correctly by running predetermined test transactions through the actual client programs. The processing is done by the client’s software, but the auditor controls the test data and evaluates the results to see if they align with expected outcomes. This setup lets the auditor assess how the software handles normal, boundary, and erroneous inputs without changing the production program. That’s why the statement describing test data being processed by the client’s programs under the auditor’s control is the best choice. The other ideas—needing many transactions of each type, covering all possible conditions, or using a different program from the one used year-round—don’t fit how the test data approach is designed to work.