Which of the following gives the best estimate of the complete cost of a compromise?

• A. ALE
• B. ARO
• C. TCI
• D. Life cycle cost

Answer: (C)

The main idea here is capturing the full financial impact of a security compromise across its entire lifecycle. Total Cost of Incident brings together direct costs (forensic work, legal fees, notifications), indirect costs (downtime, lost productivity, customer churn), and longer-term effects (reputational damage, ongoing remediation, potential future losses). It aims to quantify everything tied to that incident, not just what happens in a single year or a single category.

Annual Loss Expectancy looks at the expected cost per year by multiplying the single-loss event cost by how often such events occur; it’s a yearly average and doesn’t reflect the complete incident lifecycle or long-tail consequences. Frequency of events, captured by the annual rate of occurrence, tells you how often breaches might happen but not how costly a single breach will be. Life cycle cost covers all costs of owning a system over its life, including development and replacement, which aren’t specific to a single compromise.

So, to estimate the full financial impact of a breach, Total Cost of Incident is the best fit because it aggregates all relevant costs from the incident itself through recovery and beyond.