Which approach best assesses the effectiveness of a security control?

• A. Test against objectives, collect metrics, perform audits, and review incident histories.
• B. Install the control and never review it.
• C. Rely solely on user feedback to judge effectiveness.
• D. Ignoring historical incidents when evaluating controls.

Answer: (A)

Assessing security control effectiveness relies on evidence-based tracking that ties what the control is supposed to achieve to real measurements over time. The best approach tests the control against its objectives, collects metrics that show how well it performs (like detection rates, false positives, time to detect and respond, and coverage), conducts audits to verify proper implementation and compliance, and reviews incident histories to see how the control behaved in actual events and what gaps remain. This combination provides a clear, objective view of whether the control actually reduces risk and where to improve it.

Installing and never reviewing it leaves you in the dark about whether conditions have changed or if the control has degraded. Relying solely on user feedback is helpful for usability and perceived effectiveness but doesn’t provide the rigorous, technical evidence needed to assess security impact. Ignoring historical incidents misses patterns and lessons learned from past breaches, which are essential for understanding how well a control would perform under real threats.