To ensure that management concerns are addressed, internal audit should recommend that the data quality team review the data reported to the regulatory body first. This is because this data set is the most relevant and critical to the issue that triggered the enhancement of the data quality program. The data reported to the regulatory body should be accurate, complete, consistent, and timely, as any discrepancies could result in fines, penalties, or reputational damage for the organization. Data with customer personal information is important for data quality, but it is not directly related to the regulatory reporting issue. Data supporting financial statements is important for data quality, but it may not be the same as the data reported to the regulatory body. Data impacting business objectives is important for data quality, but it may not be as urgent or sensitive as the data reported to the regulatory body. References:
* CISA Review Manual, 27th Edition, pages 404-4051
* CISA Review Questions, Answers & Explanations Database, Question ID: 262

The recovery time objective (RTO) has a longer duration than documented in the disaster recovery plan (DRP) should be of greatest concern to the auditor when reviewing a bank's SLA with a third-party provider that hosts the bank's secondary data center. This is because the RTO is the maximum acceptable time for restoring a system or an application after a disaster or a disruption. A longer RTO than the DRP means that the bank may not be able to resume its critical business operations within the expected time frame, which may result in significant financial losses, reputational damage, customer dissatisfaction, or regulatory non- compliance12.
The SLA has not been reviewed in more than a year is not the greatest concern, although it is a good practice to review and update the SLA periodically to ensure that it reflects the current business needs and expectations, as well as any changes in the service provider's capabilities or performance. However, a lack of review does not necessarily imply a lack of compliance or quality of service, as long as the SLA is still valid and enforceable34.
Backup data is hosted online only is not the greatest concern, although it may pose some security risks if the backup data is not encrypted or protected by adequate access controls. Online backup data means that the backup data is stored on a remote server that can be accessed via the Internet, which may offer some advantages such as faster recovery, lower cost, and higher availability than offline backup data that is stored on physical media such as tapes or disks. However, online backup data also requires reliable network connectivity and bandwidth, as well as proper security measures to prevent unauthorized access or tampering56.
The recovery point objective (RPO) has a shorter duration than documented in the DRP is not the greatest concern, although it may indicate some inconsistency or misalignment between the SLA and the DRP. The RPO is the maximum acceptable amount of data loss measured in time from a disaster or a disruption. A shorter RPO than the DRP means that the bank may lose less data than expected, which may be beneficial for its business continuity and recovery. However, a shorter RPO may also imply more frequent backups, which may increase the cost and complexity of the backup process

The best situation that justifies the use of a smaller sample size when testing the accuracy of transaction data is B. It is expected that the population is error-free. The sample size is the number of items selected from the population for testing. The sample size depends on various factors, such as the level of confidence, the tolerable error rate, the expected error rate, and the variability of the population. A smaller sample size means that fewer items are tested, which reduces the cost and time of testing, but also increases the sampling risk (the risk that the sample is not representative of the population).
One of the factors that affects the sample size is the expected error rate, which is the auditor's best estimate of the proportion of errors in the population before testing. A higher expected error rate means that more errors are likely to be found in the population, which requires a larger sample size to provide sufficient evidence for the auditor's conclusion. A lower expected error rate means that fewer errors are likely to be found in the population, which allows a smaller sample size to provide sufficient evidence for the auditor's conclusion.
Therefore, if it is expected that the population is error-free (i.e., the expected error rate is zero or very low), a smaller sample size can be justified.
The other situations do not justify the use of a smaller sample size when testing the accuracy of transaction data. A. The IS audit staff has a high level of experience. The IS audit staff's level of experience does not affect the sample size, but rather their ability to design and execute the sampling procedures and evaluate the results. The IS audit staff's level of experience may affect their judgment in selecting and applying sampling methods, but it does not change the statistical or mathematical principles that determine the sample size. B.
Proper segregation of duties is in place. Proper segregation of duties is an internal control that helps prevent or detect errors or fraud in transaction processing, but it does not affect the sample size. The sample size is based on the characteristics of the population and the objectives of testing, not on the controls in place. Proper segregation of duties may reduce the likelihood or impact of errors or fraud in transaction processing, but it does not eliminate them completely. Therefore, proper segregation of duties does not justify a smaller sample size when testing the accuracy of transaction data. C. The data can be directly changed by users. The data's ability to be directly changed by users does not justify a smaller sample size, but rather a larger one. The data' s ability to be directly changed by users increases the risk of errors or fraud in transaction processing, which requires a larger sample size to provide sufficient evidence for the auditor's conclusion. The data's ability to be directly changed by users also increases the variability of the population, which affects the sample size.
References:
* ISACA, CISA Review Manual, 27th Edition, 2019, p. 2471
* ISACA, CISA Review Questions, Answers & Explanations Database - 12 Month Subscription2
* Audit Sampling - AICPA3
* How to choose a sample size (for the statistically challenged)

The best indicator of the effectiveness of an organization's incident response program is the financial impact per security event. This metric measures the direct and indirect costs associated with security incidents, such as loss of revenue, reputation damage, legal fees, recovery expenses, and fines. By reducing the financial impact per security event, the organization can demonstrate that its incident response program is effective in mitigating the consequences of security breaches and restoring normal operations as quickly as possible.
Number of successful penetration tests, percentage of protected business applications, and number of security vulnerability patches are indicators of the security posture of the organization, but they do not reflect the effectiveness of the incident response program. References: ISACA Journal Article: Measuring Incident Response Effectiveness