Reviewing and evaluating application test cases is the most effective use of an IS auditor's time during the evaluation of controls over a major application development project. Application test cases are designed to verify that the application meets the functional and non-functional requirements and specifications. They also help to identify and correct any errors, defects, or vulnerabilities in the application before it is deployed. By reviewing and evaluating the test cases, the IS auditor can assess the quality, reliability, security, and performance of the application and provide recommendations for improvement.