Auditing and Assurance: Risk, Evidence, and the Audit Opinion
The logic of an audit
Every assurance question can be traced back to one chain: risk assessment → response → evidence → conclusion. Under ISA-style risk-based auditing, you first understand the entity and its environment (including internal control) to identify risks of material misstatement (RoMM) at financial-statement and assertion level. Then you design further audit procedures - tests of controls (if you intend to rely on controls) and substantive procedures (tests of detail and substantive analytical procedures). Evidence must be sufficient (quantity) and appropriate (relevance + reliability). Reliability hierarchy: auditor's own inspection/observation > external documents > internal documents > management representations.
Traps candidates fall into
- Assertion confusion. Occurrence vs. completeness is the classic trap: testing for understatement of liabilities targets completeness; testing for overstatement of revenue targets occurrence. Cut-off is its own assertion.
- Materiality. Performance materiality is lower than overall materiality, and the trivial threshold is lower still. Questions often ask which figure to use for a specific procedure.
- Sampling. Increasing sample size reduces sampling risk but never eliminates non-sampling risk.
- Opinion types. A qualified opinion arises from material but not pervasive misstatement (or inability to obtain evidence). Pervasive issues give an adverse (misstatement) or disclaimer (scope limitation) opinion.
Rule of thumb (worked example)
A client's receivables ledger shows a balance of 5,000,000. Materiality is 100,000. You send confirmations and find a debtor of 150,000 who disputes the balance because goods were returned before year-end. Misstatement = 150,000 > materiality, and it is isolated (not pervasive) → qualified opinion on the financial statements, with the basis paragraph quantifying the effect. If the same error were one of many across all balances, making the statements misleading as a whole, you would move to adverse.
Professional scepticism
Assume neither honesty nor dishonesty; corroborate management explanations with independent evidence. Representations alone are not sufficient appropriate evidence for a material matter.