CISA Information System Auditing Process Practice Question
Which of the following is a characteristic of non-statistical (judgmental) sampling?
⚠ Common exam trap
CISA often tests the confusion between statistical and non-statistical sampling — the trap is picking 'equal chance of selection' or 'known confidence' as characteristics of judgmental sampling when those belong exclusively to statistical methods.
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
✓
The auditor uses professional judgment to select sample items
Non-statistical (judgmental) sampling is characterized by the auditor's use of professional judgment to select sample items, determine sample size, and evaluate results. Unlike statistical sampling, it does not rely on probability theory or mathematical formulas. The auditor chooses items based on risk, materiality, and experience — for example, selecting all transactions above a threshold or focusing on high-risk areas.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Every item has an equal chance of selection
Why it's wrong here
Judgmental sampling deliberately selects items based on auditor judgement, so selection is not random and probabilities are unknown; equal chance defines statistical sampling instead. It tempts because random selection is the ideal when projecting results, but this scenario asks for the defining trait of non-statistical methods.
- ✓
The auditor uses professional judgment to select sample items
Why this is correct
Judgmental sampling relies on the auditor's professional judgement, experience and knowledge of the population to select items, rather than probabilistic methods. This satisfies the stem's requirement for a non-statistical characteristic, since selection is deliberate and subjective, with no random selection or calculable sampling risk attached.
- ✗
The sample size is determined using statistical formulas
Why it's wrong here
Statistical formulas belong to statistical sampling, where probability theory determines sample size; judgmental sampling sets size from auditor judgement, experience and risk. It tempts because formula-driven sizing appears rigorous, yet it contradicts the non-statistical premise the question tests.
- ✗
The sample results can be projected to the population with known confidence
Why it's wrong here
Known-confidence projection requires probability sampling, which judgmental selection cannot provide since inclusion probabilities are undefined. It tempts because auditors do want to extrapolate findings, but that capability belongs to statistical sampling, not the judgmental characteristic being asked about.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official ISACA exam blueprint
This CISA 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 CISA exam.