A key performance indicator (KPI) is a measurable value that demonstrates how effectively an organization is achieving its key objectives. A KPI should be relevant, specific, measurable, achievable, and time-bound. The number of identified system vulnerabilities is a KPI that measures the security posture and performance of the organization’s information systems. It also helps to identify the areas that need improvement or remediation. The number of identified system vulnerabilities is relevant to the organization’s objective of protecting its information assets, specific to the system level, measurable by using tools or methods, achievable by implementing security controls or practices, and time-bound by setting a target or threshold. Aggregate risk of the organization, number of exception requests processed in the past 90 days, and number of attacks against the organization’s website are not KPIs, as they are either too broad, not relevant, or not measurable. References = Risk and Information Systems Control Study Manual, 7th Edition, Chapter 4, Section 4.1.1.1, page 1741

1: ISACA Certified in Risk and Information Systems Control (CRISC®) Exam Guide, Answer to Question 647.