Engagement Procedures and Evidence
Evidence questions test whether you can judge whether a conclusion is supportable. Expect items on evidence types, reliability, sampling, and documentation - and distractors that prize volume over quality.
Gathering and judging evidence
- Standard 2310: auditors collect internal and external information - documentary, testimonial, physical, and analytical - sufficient to support conclusions.
- Information must be sufficient (enough), reliable (from trustworthy sources), relevant, and useful; sufficiency and reliability are separate judgements.
- Reliability rises when evidence comes from an independent source, when controls over it are strong, when the auditor obtained it directly, and when source documents rather than copies are examined.
- Corroboration from two independent sources outranks several statements from the same manager.
Procedures
- Inspection, observation, confirmation, recalculation, reperformance, analytical procedures, and inquiry; inquiry alone is the weakest and should be combined.
- Analytical procedures compare current data with expectations to highlight unusual patterns; they signal where to test, not proof of cause.
- Sampling decisions must be documented, including population completeness testing; unvalidated client spreadsheets are a common evidence failure.
Documentation
- Standard 2330: workpapers must be detailed enough that an experienced auditor with no prior connection to the engagement understands what was done, what was found, and how conclusions were reached.
- Document before the engagement file closes; later additions must be dated and identified as such.
Worked example
For inventory at a third-party warehouse, the auditor has a signed management representation and a listing from the warehouse system. To support existence, the auditor should attend or observe the count and obtain confirmation directly from the warehouse operator. Management's listing is internally generated and the representation is management's own assertion; neither independently supports existence, though both corroborate an observation performed directly.
Traps that cost marks
- Ranking testimonial evidence above externally confirmed documents.
- Treating a large sample as high-quality evidence when the population is incomplete.
- Letting conclusions rest on inquiry and management representation alone.
- Documenting the work after conclusions have been drafted, losing the audit trail.