CRISC IT Risk Assessment Practice Question
During a quantitative risk analysis, the risk team calculates the loss event frequency (LEF) using the FAIR framework. If the threat event frequency (TEF) is 10 per year and the vulnerability (V) is 0.3, what is the LEF?
⚠ Common exam trap
Many exam-takers confuse the multiplicative relationship in FAIR with additive or divisive operations, or mistakenly treat vulnerability as the final frequency rather than a probability multiplier.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
3 per year
In the FAIR framework, loss event frequency (LEF) is calculated as the product of threat event frequency (TEF) and vulnerability (V). Given TEF = 10 per year and V = 0.3, LEF = 10 × 0.3 = 3 per year. This represents the expected number of loss events per year, accounting for the probability that a threat event will actually result in a loss.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
10.3 per year
Why it's wrong here
Adding TEF and vulnerability treats two different quantities as additive, but FAIR defines LEF as their product: 10 × 0.3 = 3 per year. Addition would only apply if both inputs shared the same unit and meaning, which frequency and probability do not.
- ✗
30 per year
Why it's wrong here
LEF is derived by multiplying TEF by vulnerability, giving 10 × 0.3 = 3 per year, not 30. Multiplying by the complement (0.7) or by ten again inflates the result; 30 would arise only if vulnerability equalled 3, which is impossible since it is a probability between 0 and 1.
- ✗
0.3 per year
Why it's wrong here
This simply restates the vulnerability value rather than computing LEF. The FAIR formula requires multiplying threat event frequency by vulnerability: 10 × 0.3 = 3 loss events per year. Vulnerability alone describes the proportion of threat events that become losses, not their annual frequency.
- ✓
3 per year
Why this is correct
In FAIR, loss event frequency derives from threat event frequency multiplied by vulnerability, so 10 × 0.3 yields 3 loss events per year. This satisfies the stem's quantitative requirement, converting ten annual threat events into the subset that actually becomes losses given the 0.3 vulnerability rate.
Go deeper
Related to this question
About these practice questions
One of 1,062 original CRISC practice questions on Courseiva, each with a full explanation and wrong-answer analysis — not exam dumps or protected exam content. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This CRISC practice question is part of Courseiva's free ISACA certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the CRISC exam.