The number of emergency change requests is the most important factor to review when confirming whether implemented controls are operating effectively, as it indicates the frequency and severity of incidents or issues that require urgent changes to the controls, and may reflect the control deficiencies or failures. The results of benchmarking studies, the results of risk assessments, and the maturity model are not the most important factors, as they are more related to the comparison, evaluation, or improvement of the controls, respectively, rather than the confirmation of the control effectiveness. References = CRISC Review Manual, 7th Edition, page 154.

Residual risk is the risk that remains after the risk response has been implemented. Risk tolerance is the acceptable level of variation from the desired outcome or objective. If the residual risk is within the risk tolerance, it means that the risk response has been effective in reducing the risk to an acceptable level.
References
*ISACA CRISC Review Manual, 7th Edition, Domain 3: Risk Response, Section 3.1.1: Residual Risk
*Residual Risk: Definition, Formula & Management - Video & Lesson Transcript | Study.com
*Risk Tolerance - ISACA

A preventive control is a type of control that aims to avoid or reduce the occurrence of an undesirable event or risk. A preventive control can be implemented through technical, administrative, or physical means. A new policy that forbids copying of data onto removable media is an example of a preventive control, because it prevents unauthorized data exfiltration or leakage through removable devices, such as flash drives or external hard disk drives. A preventive control is different from the other types of controls, as explained below:
* A detective control is a type of control that aims to discover or identify the occurrence of an undesirable event or risk. A detective control can be implemented through monitoring, auditing, or reporting activities. An example of a detective control is a log analysis tool that detects any unauthorized access or modification of data on a system.
* A directive control is a type of control that aims to guide or instruct the behavior or actions of individuals or groups. A directive control can be implemented through policies, procedures, standards, or rules. An example of a directive control is a training program that teaches employees how to handle sensitive data securely and appropriately.
* A deterrent control is a type of control that aims to discourage or dissuade individuals or groups from performing an undesirable event or risk. A deterrent control can be implemented through sanctions, penalties, or consequences. An example of a deterrent control is a warning message that informs users of the legal implications of copying data onto removable media without authorization. References = Risk and Information Systems Control Study Manual, Chapter 2, Section 2.2.1, page 38.

IT risk assessments can best be used by management as input for decision-making, because they provide valuable information about the current and potential risks facing the organization's IT systems, networks, and data, and their impact on the organization's objectives and performance. IT risk assessments can help management to identify and prioritize the most critical and relevant risks, and to evaluate and select the most appropriate and effective risk responses. IT risk assessments can also help management to allocate and optimize the resources and budget for IT risk management, and to communicate and report the risk status and performance to the senior management, the board of directors, and other stakeholders. IT risk assessments can support management in making informed and balanced decisions that consider both the opportunities and the threats of IT-related activities and investments. References = Complete Guide to IT Risk Management 1

A three lines of defense structure is a model that defines the roles and responsibilities of different functions and levels within an organization for risk management and control. The first line of defense is the operational management, which is responsible for owning and managing the risks. The second line of defense is the risk management and compliance functions, which are responsible for overseeing and supporting the risk management processes. The third line of defense is the internal audit function, which is responsible for providing independent assurance on the effectiveness of the risk management and control systems. The greatest benefit of a three lines of defense structure is that it provides clear accountability for risk management processes, as it clarifies who is responsible for what, and how they interact and communicate with each other. This can help to avoid duplication, confusion, or gaps in the risk management activities, and ensure that the risks are properly identified, assessed, treated, monitored, and reported. References = CRISC Review Manual, 7th Edition, page 107.