Annualized loss resulting from security incidents is the most appropriate metric to demonstrate the effectiveness of information security controls to senior management, as it quantifies the financial impact of security breaches on the organization's assets, operations, and reputation. This metric helps to communicate the value of security investments, justify the security budget, and prioritize the security initiatives based on the potential loss reduction. Annualized loss resulting from security incidents can be calculated by multiplying the annualized rate of occurrence (ARO) of an incident by the single loss expectancy (SLE) of an incident. ARO is the estimated frequency of an incident occurring in a year, and SLE is the estimated cost of an incident. For example, if an organization estimates that a ransomware attack may occur once every two years, and that each attack may cost $100,000 to recover, then the annualized loss resulting from ransomware attacks is $50,000 ($100,000 / 2).
References = CISM Review Manual 2022, page 3171; CISM Exam Content Outline, Domain 4, Knowledge Statement 4.112; Key Performance Indicators for Security Governance, Part 1; Performance Measurement Guide for Information Security