The BEST way for an organization to ensure that incident response teams are properly prepared is by conducting tabletop exercises appropriate for the organization.
Tabletop exercises are an effective way to test and validate an organization's incident response plan (IRP) and the readiness of the incident response team. These exercises simulate different scenarios in a controlled environment and allow the team to practice their response procedures, identify gaps, and make improvements to the plan. By conducting regular tabletop exercises, the incident response team can stay current with changes in the threat landscape and ensure that they are prepared to respond to incidents effectively.
According to the Certified Information Security Manager (CISM) Study Manual, "Tabletop exercises are a valuable tool for testing and validating the effectiveness of the IRP and the readiness of the incident response team. These exercises simulate different scenarios in a controlled environment and allow the team to practice their response procedures, identify gaps, and make improvements to the plan." While providing training from third-party forensics firms, obtaining industry certifications, and documenting multiple scenarios for the organization and response steps can all be useful in preparing incident response teams, they are not as effective as conducting tabletop exercises appropriate for the organization.
Reference:
Certified Information Security Manager (CISM) Study Manual, 15th Edition, Page 324.

The number of reported incidents has increased is the best evidence that a recently established information security program is effective because it indicates that the organization has improved its detection and reporting capabilities and has raised awareness among employees about security issues. Regular IT balanced scorecards are communicated is not a good evidence because it does not measure the actual performance or outcomes of the security program. Senior management has reported fewer junk emails is not a good evidence because it does not reflect the overall security posture or maturity of the organization. The number of tickets associated with IT incidents have stayed consistent is not a good evidence because it does not show any improvement or reduction in security incidents or risks. References: https://www.isaca.org/resources/isaca- journal/issues/2016/volume-6/how-to-measure-the-effectiveness-of-information-security-using-iso-27004
https://www.isaca.org/resources/isaca-journal/issues/2014/volume-6/how-to-measure-the-effectiveness-of- your-information-security-management-system

A parallel test is the best method to evaluate the effectiveness of an alternate processing site when continuous uptime is required. A parallel test involves processing the same transactions or data at both the primary and the alternate site simultaneously, and comparing the results for accuracy and consistency. A parallel test can validate the functionality, performance, and reliability of the alternate site without disrupting the normal operations at the primary site. A parallel test can also identify and resolve any issues or discrepancies between the two sites before a real disaster occurs. A parallel test can provide a high level of assurance and confidence that the alternate site can support the organization's continuity requirements.
References = CISM Review Manual, 16th Edition, Chapter 3: Information Security Program Development and Management, Section: Business Continuity Plan (BCP) Testing, page 1861; CISM Review Questions, Answers & Explanations Manual, 10th Edition, Question 56, page 522.
A parallel test is the best method to evaluate the effectiveness of an alternate processing site when continuous uptime is required because it involves processing data at both the primary and alternate sites simultaneously without disrupting the normal operations1. A full interruption test would cause downtime and potential loss of data or revenue2. A simulation test would not provide a realistic assessment of the alternate site's capabilities3. A tabletop test would only involve a discussion of the procedures and scenarios without actually testing the site4.
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The risk owner is the best positioned to be accountable for risk acceptance decisions based on risk appetite, because the risk owner is the person or entity with the accountability and authority to manage a risk1. The risk owner is responsible for evaluating the risk level, comparing it with the risk appetite, and deciding whether to accept, avoid, transfer, or mitigate the risk2. The risk owner is also accountable for monitoring and reporting on the risk status and outcomes3. The information security manager, the chief risk officer (CRO), and the information security steering committee may have some roles and responsibilities in the risk management process, but they are not the primary accountable parties for risk acceptance decisions.
References = CISM Review Manual, 16th Edition, page 754; Risk Acceptance

= A security exception is a formal authorization to deviate from a security policy, standard, or control, due to a valid business reason or requirement. The primary reason for granting a security exception is that the risk associated with the deviation is justified by the benefit to the business, such as increased efficiency, productivity, customer satisfaction, or competitive advantage. The security exception should be approved by the appropriate authority, such as the senior management or the risk committee, based on a risk assessment and a cost-benefit analysis. The security exception should also be documented, communicated, monitored, and reviewed periodically123. References =
* 1: CISM Review Manual 15th Edition, page 364
* 2: CISM Practice Quiz, question 1132
* 3: Security Policy Exception Management, section "Security Policy Exception Management Process"